Blender 3D: Noob to Pro/Procedural Eyeball in Cycles
Knowing before Making
Blender is a powerful and complex 3D modeling and rendering package. Before you can use it effectively to make things, you need to know a few things about how it works:
- the process of 3D modeling and rendering (what Blender does)
- some rudiments of 3D analytic geometry (axis and coordinates)
- orthographic and perspective views of a 3D object
- local coordinate systems and child objects
- the fundamentals of Blender's user interface (hotkeys, windows, and menus)
- how to view a 3D scene from different vantage points (in Blender)
This unit is devoted entirely to this sort of background knowledge. You won't create your first Blender model until the next unit.
Knowing this, you might be tempted to skip ahead. Depending on your background, that may or may not work. For instance, if you've used other 3D graphics packages, you might be able to skim (or skip) ahead as far as the user interface tutorial. But if there's any doubt, please proceed through the tutorials in sequence.
Blender is not the kind of software you can launch into and grope about until you find your way. It's not like exploring an unfamiliar city. It's more like flying a spaceship. If you hop into the pilot's seat without knowing the fundamentals, you'll be lucky to ever get off the ground, and it'd take a miracle for you to reach your destination safely.
A Word about Jargon
Like any subject, 3D modeling has its own jargon: terminology specific to the subject and ordinary words that have special meanings in the context of computer graphics.
In this book, important new words are highlighted on first appearance and defined soon after. If you suspect you've missed (or forgotten) the meaning of a word, try looking it up in the Glossary.
Things You'll Need
In order to work through the tutorials, you'll need access to a computer that has Blender installed (download the latest stable release).
Depending on what is installed on your system, you may also need the appropriate Python installation. Each version of Blender works with only one specific version of Python, which is generally included in the download.
|Blender version||Python version|
After the installation process is finished, Blender should appear in the Graphics section of your desktop environment application menu.
It's a good idea to have pencil and paper handy for sketching and taking notes. There's a lot to absorb. Taking notes as you go will pay dividends later.
Where to Go for Help
Many modules have a section like this at the bottom, listing websites with information on the topics covered in the module.
- Blender system requirements
- the GIMP wikibook
- Windows installation
- Linux installation
- OSX installation
- About the Python programming language
What Blender Can Do
In this module, you'll learn what Blender does, both in terms of the product (images) and the process (3D modeling).
Blender is a free software package for authoring "three-dimensional" (3D) graphics (also known as computer graphics or “CG”), including still images, games, and video.
While the end-product of most Blender projects is a two-dimensional (2D) raster image on a flat surface (be it a monitor, movie screen, or sheet of paper) except for Head Mounted Virtual Reality applications, the images are said to be "3D" because they exhibit the illusion of depth. In other words, someone looking at the image can easily tell which parts are meant to be closer and which are farther away.
Here's a realistic still image that was authored with Blender.
Look closely at the building.
- Because it is obscured by the building, you can tell that the tree-lined hillside is behind the building instead of vice versa.
- The way the top and bottom edges of the front wall appear to converge toward the base of the tree allow you to judge the angle between the front wall and your viewpoint.
- Your brain interprets dark portions of the wall as shadows, allowing you to estimate where the light is coming from, even though the sun is outside the frame of the image.
While an illusion of depth can be authored by hand with 2D graphics software (or a paintbrush!), Blender provides a much easier way.
It's likely that the lonely house never existed outside of the artist's mind. Instead of building a big set on a rural lot in Germany, waiting for the right light, and photographing it, the author built a scene in a virtual 3D world—one contained inside a computer. This is called CGI (Computer Generated Imagery). He or she then used Blender to render the scene (convert it into a 2D image). You can view more of what Blender can do at the Blender gallery: http://www.blender.org/features/
Steps in the 3D Production Process
To produce an image like the one above involves two major steps to start with:
- Modelling, which is the creation of your miniature 3D world, also known as a model or scene. This involves defining the geometry of the objects, making it look like they are made out of particular materials, setting up the lighting, and defining a camera viewpoint.
- Rendering, which is the actual generation of the image of the world from the viewpoint of the camera (taking a “photograph” of the scene, if you like), for your audience to enjoy.
3D is often used to produce not just single still images, but animations as well. This requires some additional steps:
- Rigging — setting up a rig, namely a way of deforming (changing the shape of) a character in various repeatable ways to convincingly mimic joint movements, facial expressions and other such actions of real-life people or animals.
- Posing — choreographing the positions of the objects and their parts in the 3D scene over time, using the previously-created animation rigs
- Rendering now involves creating a whole sequence of frames representing movement over time, rather than just a single still frame.
But that’s not all. There are frequently additional processes to embellish the results of the above, to make them look more realistic:
- Sculpting — a more organic form of modelling objects by shaping them as though they were made out of clay. This produces more complicated, irregular shapes which mimic real objects found in nature, as opposed to clean, simple, geometrical ones which mostly only exist in the world of mathematics.
- Texture painting — You’re probably familiar with programs that let you paint an image on a 2D digital canvas. Such programs are commonly used in 3D production, to create textures which are “wrapped” around the surfaces of 3D objects to give them a more interesting appearance. 3D programs also often allow direct painting on the surfaces of those objects, so the effect of the design can be observed immediately, instead of having to go through a separate paint-on-a-flat-surface-then-wrap sequence of steps.
- Physical modelling — simulating the behaviour of real-world objects subject to real-world forces, for example hard balls colliding, soft cloth draping itself over an obstacle under gravity, water flowing and pouring. Mathematical formulas are available for these that give results very close to real life, all you need is the computing power to calculate them.
- Motion capture, or mocap: producing convincing animations, particularly ones that look like the movements of real people (walking, running, dancing etc) can be hard. Hence the technique of capturing the motions of live actors, by filming them with special markers attached to strategic points on their bodies, and doing computer processing to track the movements of these markers and convert them to corresponding movements of an animation rig.
- Compositing — this is where 3D renders are merged together with real photographic/live-action footage, to make it look like a rendered model is in the middle of a real-world scene, or conversely a real live actor is in the middle of a rendered scene. If done with proper skill, in particular due care to matching the effects of lights and shadows, the viewer becomes unable to tell what is real and what is not!
And just to add another complication to the mix, there are two kinds of rendering:
- Real-time rendering is rendering that has to happen under tight time constraints, typically for interactive applications like video gaming. For example, most gamers expect the screen to be updated 60 times per second in order to render smooth motion and respond quickly enough to player actions. These time constraints impose major limitations on the kinds of rendering techniques that can be used.
- Non-real-time rendering is where the time constraints are not so tight, and quality is the overriding factor. For example, when producing a single still frame, it may not matter so much that it takes minutes or hours to do so, because the beauty and detail of the final image is worth it. When rendering a Hollywood-quality movie, it may still take hours per frame, but the use of a renderfarm of hundreds or thousands of machines, all working on different frames at the same time, allows the entire sequence to complete in just a few weeks.
But wait, there’s more: There are also some areas, which might be considered to be stepping outside of traditional 3D production work, where Blender provides functionality:
- Video editing — having rendered your animation sequences and shot your live-action footage, you will want to combine them in a properly-timed linear sequence to tell a coherent story.
- 3D printing — Though still in its early days yet, many people are already experimenting with creating objects using 3D printers. The shape data may be obtained from real objects with 3D scanning, or it may be created from scratch using 3D modelling, or you can even combine both processes.
Blender is a capable tool for every single one of these processes. There’s quite a lot there, isn’t there? But don’t be too intimidated: this Wikibook will take things step by step, and you will be able to produce some fun stuff from early on.
- 3D rendering at Wikipedia.
- Comparison of 3D computer graphics software at Wikipedia.
- Computer-generated imagery at Wikipedia.
- Depth perception at Wikipedia.
- Blender Art Gallery
- Blender Homepage
If you haven't previously studied 3D graphics, technical drawing, or analytic geometry, you are about to learn a new way of visualizing the world, an ability that's fundamental to working with Blender or any 3D modeling tool.
3D modeling is based on geometry, the branch of mathematics concerned with spatial relationships, specifically analytical geometry, which expresses these relationships in terms of algebraic formulas. If you have studied geometry, some of the terminology will be familiar.
Coordinates And Coordinate Systems
Look around the room you’re in. The odds are it will have a cuboidal shape, with four vertical walls at right angles to each other, a flat, horizontal floor, and a flat, horizontal ceiling.
Now imagine there’s a fly buzzing around the room. The fly is moving in three-dimensional space. In mathematical terms, that means its position within the room at any given moment, can be expressed in terms of a unique combination of three numbers.
There are an infinite number of ways —coordinate systems— in which we could come up with a convention for defining and measuring these numbers, i.e. the coordinates. Each convention will yield different values even if the fly is in the same position. Coordinates only make sense with reference to a specific coordinate system! To narrow down the possibilities (in a purely arbitrary fashion), let us label the walls of the room with the points of the compass: in a clockwise direction, North, East, South and West. (If you know which way really is north, feel free to use that to label the walls of your room. Otherwise, choose any wall you like as north.)
Consider the point at floor level in the south-west corner of the room. We will call this (arbitrary) point the origin of our coordinate system, and the three numbers at this point will be '"`UNIQ--postMath-00000001-QINU`"'. The first of the three numbers will be the distance (in some suitable units, let’s say meters) eastwards from the west wall, the second number will be the distance north from the south wall, and the third number will be the height above the floor.
Each of these directions is called an axis (plural: axes), and they are conventionally labelled X, Y and Z, in that order. With a little bit of thought, you should be able to convince yourself that every point within the space of your room corresponds to exactly one set of '"`UNIQ--postMath-00000002-QINU`"' values, and that every possible combination of '"`UNIQ--postMath-00000003-QINU`"' values, with '"`UNIQ--postMath-00000004-QINU`"', '"`UNIQ--postMath-00000005-QINU`"' and '"`UNIQ--postMath-00000006-QINU`"' (where '"`UNIQ--postMath-00000007-QINU`"' is the east-west dimension of your room, '"`UNIQ--postMath-00000008-QINU`"' is its north-south dimension, and '"`UNIQ--postMath-00000009-QINU`"' is the height between ceiling and floor) corresponds to a point in the room.
The following diagram illustrates how the coordinates are built up, using the same colour codes that Blender uses to label its axes: red for X, green for Y and blue for Z (an easy way to remember this if you're familiar with RGB is the order -- Red X, Green Y, Blue Z). In the second picture, the x value defines a plane parallel to the west wall of the room. In the third picture, the y value defines a plane parallel to the south wall, and in the fourth picture, the z value defines a plane parallel to the floor. Put the planes together in the fifth picture, and they intersect at a unique point.
Another simple way to understand what the coordinates of a point say (x,y,z) means is, if one starts from origin and moves x, y, and z units of distance parallel to x, y, and z axes respectively, in any sequence, one will reach that point. Thus, for example, a coordinate of (3,4,5) means the point which is reached when one moves, starting from origin, 3 units of distance along x-axis, 4 units of distance along y-axis and 5 units of distance along z-axis.
This style of coordinate system, with the numbers corresponding to distances along perpendicular axes, is called Cartesian coordinates, named after René Descartes, the 17th-century mathematician who first introduced the concept. Legend has it that he came up with the idea after watching a fly buzzing around his bedroom!
There are other ways to define coordinate systems, for example by substituting direction angles in place of one or two of the distance measurements. These can be useful in certain situations, but usually all coordinate systems in Blender are Cartesian. However, in Blender, switching between these coordinate systems is simple and easy to do.
Can coordinate values be negative? Depending on the situation, yes. Here we are only considering points within our room. But suppose instead of placing our origin in the bottom southwest corner, we put it in the middle of the room, halfway between the floor and ceiling. (After all, it is an arbitrary point, we can place it wherever we like, as long as we agree on its location.) If the X-coordinate is the distance east from the origin, how do we define a point west of the origin? We simply give it a negative X-coordinate. Similarly, points north of the origin have a positive Y-coordinate, those south of it, have negative Y-coordinates. Points above the origin have a positive Z-coordinate, those below it, a negative Z-coordinate.
Handedness Of Coordinate Systems
It is conventional for most Cartesian coordinate systems to be right-handed. To understand this, hold the thumb, index finger and middle finger of your right hand perpendicular to each other:
Now orient your hand so your thumb points along the X-axis in the positive direction (direction of increasing coordinate numbers), your index finger along the positive Y-axis, and your middle finger along the positive Z-axis. Another way of looking at it is, if you placed your eye at the origin, and you could see the three arrows pointing in the directions of positive X, positive Y and positive Z as in Figure 1, the order X, Y, Z would go counter clockwise.
Another way to visualize this is to make a fist with your right hand, with your curled fingers towards you. Stick out your thumb directly to the right (X). Now aim your pointer finger straight up (Y). Finally, make your middle finger point toward yourself (Z). This is the view from directly above the origin.
Axes Of Rotation
Consider a spinning sphere. Every point on it is moving, except the ones along the axis. These form a motionless line around which the rest of the sphere spins. This line is called the axis of rotation.
More precisely, the axis of rotation is a point or a line connecting points that do not change position while that object rotates, drawn when the observer assumes he/she does not change position relative to that object over time.
Conventionally, the direction of the axis of rotation is such that if you look in that direction, the rotation appears clockwise, as illustrated below, where the yellow arrow shows the rotational movement, while the purple one shows the rotation axis:
To remember this convention, hold your right hand in a thumbs-up gesture:
If the rotation follows the direction of your curled fingers, then the direction of the axis of rotation is considered to be the same as the direction which the thumb is pointing in.
This gesture is a different form of the right-hand rule and is sometimes called the right-hand grip rule, the corkscrew-rule or the right-hand thumb rule. From now on we will refer to it as 'the right-hand grip rule'.
When describing the direction of a rotating object, do not say that it rotates left-to-right/clockwise, or right-to-left/counterclockwise. Each of these on their own are meaningless, because they're relative to the observer. Instead of saying this, find the direction of the axis of rotation and draw an arrow to represent it. Those who know the right-hand grip rule will be able to figure out what the direction of rotation of the object is, by using the rule when interpreting your drawing.
- the Geometry wikibook
- Analytic geometry at Wikipedia.
- Cartesian coordinate system at Wikipedia.
- Right-hand rule at Wikipedia.
- Rotation at Wikipedia.
A transformation is any operation that changes coordinate values in some way. For example, if you pick up an object and move it to a different place in the room without changing its orientation, then the coordinates of each point on the object relative to the room are adjusted by an amount that depends on the distance and direction between the old and new positions. This is called a translation transformation.
Simply turning the object without moving it from its original location is called rotation.
If the object were to get bigger or smaller, that is a scaling transformation. In the real world, only a few objects can be scaled in this way. For example, a balloon can be inflated or deflated to a larger or smaller size, but a bowling ball cannot. Regardless of what can and can't be re-sized in the real world, any object can be scaled (re-sized) in the world of computer graphics. Scaling may be uniform, i.e. apply equally in all dimensions, or non-uniform.
The main types of coordinate transformations we’re concerned with are called linear transformations. Lines that were straight before the transformation remain straight. i.e. they do not become curved. For example, the following diagram illustrates three linear transformations applied to the square in the center: Clockwise from the left, a shear or skew, a scale, and a rotation, plus one non-linear transformation that causes two sides of the box to become curved.
It is possible to concatenate or compose a series of transformations. The resulting transformation can do many things in one operation — translation, rotation, scaling etc. However, the order of composition of the component transformations becomes important. In general, transformations are not commutative. For example, compare the result of moving our model some distance along the Y axis followed by rotating it about the X axis (If this doesn't make sense, consider that the axes are fixed, they aren't moving with the object. More on that later Global and local coordinates):
versus the result of doing the rotation first:
In some instances, the three forms of transformation may be applied on a single object concurrently. Such a feature exists in Blender and is normally implemented in creating animations. For example, you can decide to pick up the object (first transformation - translation), twist it (second transformation - rotation), and, in a 3D modeling environment, increase the size of the object (third transformation - scaling).
Often there is a need to find the inverse of a transformation. That is, a transformation that has the opposite effect. For example, a rotation of +45° about the X axis is undone by a rotation of -45° around the same axis.
Inverses have many uses, one of which is to simplify the construction of certain kinds of transformations.
For example, it is easy to construct a rotation transformation about the X, Y or Z-axis of the coordinate system. But what about a rotation of Θ° around an arbitrary axis? This can be made out of the following parts:
- a translation that makes the rotation axis pass through the origin.
- rotations about the Y and/or Z axes, as appropriate, so the rotation axis lies along the X axis.
- a rotation of Θ° about the X axis.
- the inverse of the rotations that aligned the rotation axis with the X axis.
- the inverse of the translation that made the rotation axis pass through the origin.
Most of the transformations we deal with in 3D modelling have an inverse, but not all. See the next section for some that don’t.
Most of our display and output devices are not three-dimensional. Thus, three-dimensional images need to be projected onto a two-dimensional surface (like a display screen or a printed page) before we can see them.
There are two main ways to perform such projections. One is orthographic projection, where parallel lines are drawn from all points of the three-dimensional object until they intersect a plane representing the display surface:
The other way is perspective projection, where the lines drawn are not parallel, but intersect at a point representing the location of the eye of the viewer:
Projections are also linear transformations. But since they take a three-dimensional space and flatten it onto a two-dimensional surface, some information is lost. Those transformations are non-invertible i.e. they cannot be undone, at least in a unique way as the depth information is gone.
The mathematics of perspective were first worked out in the 11th century by Alhazen, and used to great effect by the Italian Renaissance painters four hundred years later.
Blender provides two different ways of viewing 3D scenes:
- orthographic view
- perspective view.
In order to use them effectively, you need to understand their properties.
An orthographic view (or projection) of a 3D scene is a 2D picture of it in which parallel lines appear parallel, and all edges perpendicular to the view direction appear in proportion, at exactly the same scale.
Orthographic views are usually aligned with the scene's primary axes. Edges parallel to the view axis disappear. Those parallel to the other primary axes appear horizontal or vertical. The commonly used orthographic views are front, side, and top views, though back and bottom views are possible.
Uniform scale makes an orthographic view very useful when constructing 3D objects, not only in computer graphics, but also in manufacturing and architecture.
Here's one way to think about the orthographic view:
Imagine photographing a small 3D object through a telescope from a very great distance. There would be no foreshortening. All features would be at the same scale, regardless of whether they were on the near side of the object or its far side. Given two (or preferably three) such views, along different axes, you could get an accurate idea of the shape of the object, useful for "getting the feel" of objects in a virtual 3D world where you're unable to touch or handle anything!
Here is a drawing of a staircase:
and here are three orthographic views of the same staircase, each outlined in red:
The views are from the front, top, and left. Dashed lines represent edges that, in real life, would be hidden behind something, such as the left wall of the staircase. (Think of each view as an X-ray image.)
The leading edges of the steps are visible in both the front and top views. Note that they appear parallel and of equal length in 2D, just as they are in 3D reality.
- Orthographic projection at Wikipedia.
As you know, the main reason for modeling 3D objects in Blender is to render images that exhibit the illusion of depth.
Orthographic views are great for building a house, but seriously flawed when it comes to creating realistic images of the house for use in a sales brochure. While a builder wants blueprints that are clear and accurate, a seller wants imagery that's aesthetically pleasing, with the illusion of depth. Blender makes it easy to use tricks like perspective, surface hiding, shading, and animation to achieve this illusion.
How does perspective work?
The essence of perspective is to represent parallel edges (in a 3D scene) by edges (in the 2D image) that are not parallel. When done correctly, this produces foreshortening (nearby objects are depicted larger than distant ones) and contributes to the illusion of depth.
Perspective is challenging to draw by hand, but Blender does it for you, provided you give it a 3D model of the scene and tell it where to view the scene from.
If you're confident you understand perspective, you can skip the rest of this module and proceed to the "Coordinate Spaces in Blender" module.
Blender only does 3-point perspective, not 1-point or 2-point.
Drawing classes teach various kinds of perspective drawing: one-point perspective, two-point perspective, and three-point perspective. In this context, the word "point" refers to what artists call the vanishing point.
When you're looking at a 3D object head-on and it's centered in your view, that is an example of one-point perspective.
Imagine looking down a straight and level set of train tracks. The tracks appear to converge at a point on the horizon. This is the vanishing point.
The image on the right is a 2D image of a cubic lattice or framework. Like any cube, it has six square faces and twelve straight edges. In the 3D world, four of the edges are parallel to our line-of-sight. They connect the four corners of the nearest square to the corresponding corners of the farthest one. Each of these edges is parallel to the other three.
In the 2D image, those same four edges appear to converge toward a vanishing point, contributing to the illusion of depth. Since this is one-point perspective, there is a single point of convergence at the center of the image.
Now the cube is at eye level, and you're near one of its edges. Since you're not viewing it face-on, you can't draw it realistically using one-point perspective. The horizontal edges on your left appear to converge at a point on the horizon to the left of the cube, while those on the right converge to the right. To illustrate the cube with a good illusion of depth, you need two vanishing points.
Now imagine you're above the cube near one of its corners. To draw it, you'd need three vanishing points, one for each set of parallel edges.
From that perspective, there are no longer any edges which appear parallel. The four vertical edges, the four left-right edges, and the four in-out edges each converge toward a different vanishing point.
- Perspective (graphical) at Wikipedia.
Coordinate Spaces in Blender
We'll start looking at how 3D scenes are represented in Blender.
As was explained in the "3D Geometry" module, Blender represents locations in a scene by their coordinates. The coordinates of a location consist of three numbers that define its distance and direction from a fixed origin. More precisely:
- The first (or x-) coordinate of the location is defined as its distance from the YZ plane (the one containing both the Y and Z axes). Locations on the +X side of this plane are assigned positive x-coordinates, and those on the -X side are given negative ones.
- Its second (or y-) coordinate is its distance from the XZ plane, with locations on the -Y side of this plane having negative y-coordinates.
- Its third (or z-) coordinate is its distance from the XY plane, with locations on the -Z side of this plane having negative z-coordinates.
Thus the origin (which lies at the junction of all three axes and all three planes) has the coordinates (0, 0, 0).
Global and local coordinates
Blender refers to the coordinate system described above as the global coordinate system, though it's not truly global as each scene has its own global coordinate system. Each global coordinate system has a fixed origin and a fixed orientation, but we can view it from different angles by moving a virtual camera through the scene and/or rotating the camera.
Global coordinates are adequate for scenes containing a single fixed object and scenes in which each object is merely a single point in the scene. When dealing with objects that move around (or multiple objects with sizes and shapes), it's helpful to define a local coordinate system for each object, i.e. a coordinate system that can move with, and follow the object. The origin of an object's local coordinate system is often called the center of the object although it needn't coincide with the geometrical center of the object.
3D objects in Blender are largely described using vertices (points in the object, singular form: vertex). The global coordinates of a vertex depend on:
- the (x, y, z) coordinates of the vertex in the object's local coordinate system
- the location of the object's center
- any rotation (turning) of the local coordinates system relative to the global coordinate system, and
- any scaling (magnification or reduction) of the local coordinate system relative to the global coordinate system.
For example, the teacup in Figure 1 is described by a mesh model containing 171 vertices, each having a different set of local (x, y, z) coordinates relative to the cup's center. If you translate the cup (move it without rotating it), the only bits of the model that have to change are the global coordinates of the center. The local coordinates of all its vertices would remain the same.
Coordinates of child objects
Any object can act as a parent for one or more other objects in the same scene, which are then referred to as its children. (An object cannot have more than one direct parent, but parent objects may themselves be the children of other objects.)
If an object has a parent, its position, rotation, and scaling are measured in the parent's local coordinate system, almost as if it were a vertex of the parent. i.e. the position of the child's center is measured from the parent's center instead of the origin of the global coordinate system. So if you move a parent object, its children move too, even though the children's coordinates have not changed. The orientation and scaling of a child's local coordinate system are likewise measured relative to those of its parent. If you rotate the parent, the child will rotate (and perhaps revolve) around the same axis.
Parent-child relationships between objects make it simpler to perform (and animate) rotations, scaling and moving in arbitrary directions. In Fig. 1b the teacup is a child object of the coordinate cross on the right. That cross is itself the child of an invisible parent. (It is both a parent and child.) In the cup's local coordinate system, it is not rotating, but as the cross on the right rotates around its Z axis, it causes the cup to rotate and revolve. In real animations, it will be much easier when the character holding the cup rotates, the cup changes its position respectively.
Taking the viewer of the scene into consideration, there is another coordinate space: the view coordinates. In Fig. 2 the viewer is symbolized by the camera. The Z axis of the view coordinates always points directly to the viewer in orthographic projection. The X axis points to the right, the Y axis points upwards (Fig. 3).
In fact you always work in view coordinates if you don't set it any other way*. This is particularly useful if you have aligned your view prior to modeling something, e.g. if an object has a slanted roof and you want to create a window to fit in that roof, it would be very complicated to build the window aligned to the local coordinate system of the object, but if you first align your view to the slanted roof, you can easily work in that view coordinate system.
(* In the Blender 2.6 series, the default has been changed to global coordinates. View coordinates remain as an option.)
If you work in one of the three standard views (Front/Top/Side) the alignment of the view coordinates fits the global coordinates. Therefore, it is quite natural to model in one of the standard views and many people find this the best way to model.
Although Blender is a 3D program, only objects' faces are visible. The orientation of the faces is important for many reasons. For example, in our daily lives it seems quite obvious that a book lies flat on a table. This requires the surface of the table and that of the book to be parallel to each other. If we put a book on a table in a 3D program, there is no mechanism that forces these surfaces to be parallel. The artist needs to ensure that.
The orientation of a face can be described with the help of the so-called surface normal. It is always perpendicular to the surface. If several faces are selected, the resulting normal is averaged from the normals of every single face. In Fig. 4 the normal coordinates of the visible faces are drawn.
This concept can be applied to individual points on the object, even if the points themselves have no orientation. The normal of a point is the average of normals of the adjacent faces.
In later parts (for example, talking about textures) you will come across coordinates labelled “U” and “V”. These are simply different letters chosen to avoid confusion over “X”, “Y” and “Z”. For example, a raster image is normally laid out on a flat, two-dimensional plane. Each point on the image can be identified by X and Y coordinates. But Blender can take this image and wrap it around the surface of a 3D object as a texture. Points on/in the object have X, Y and Z coordinates. So to avoid confusion, the points on the image are identified using U and V to label their coordinates instead of X and Y. We then refer to “UV mapping” as the process of determining where each (U, V) image point ends up on the (X, Y, Z) object.
Blender's user interface (the means by which you control the software) is not particularly easy to learn. However, it has improved over time and is expected to continue doing so. The current version of the Blender software is available for download from the Blender Foundation's website.
The tutorials in this section will familiarize you with the basics of the user interface. By the end of this section, you should be able to:
- resize, split, and merge any Blender window;
- change the type of any Blender window;
- access user preferences;
- access panels containing buttons and other controls;
- change the viewpoint of a viewport.
For those new to Blender, this is a fundamental section of the book.
Advice on Customization
Blender is a complex software package with many customizable features. You can customize the user interface to assign new functions to buttons and hotkeys. In fact, you can change almost anything to suit yourself. However, this complicates the giving and following of directions. It is recommended you adhere to the default screen arrangements of Blender in order to be able to follow the remaining parts of these tutorials. Blender ships with 4 to 5 screen-content arrangements which are suitable for almost any kind of job you'll want to use it for - from creating motion and animation to making games.
We recommend leaving Blender's user interface in its "factory settings" while working through the Noob to Pro tutorials. At the very least, wait until you've mastered the basics before you customize the interface - and we know you definitely will when you master it!
Keystroke, Button, and Menu Notation
As you read through these tutorials, you will encounter cryptic codes such as+ and Timeline → End Frame. They describe actions you perform using the keyboard and mouse. The notation used in this book comes from the standard used by the Blender community. We will try to import those standards here to facilitate our studies.
If you're reading this book online, you may wish to print this page for future reference. In addition, you can bookmark it in your browser for faster reference.
Most computer keyboards have number keys in two different places. A row above the letters, and in a numpad (numeric keypad) to the right of the keyboard. While many applications use these two sets of keys interchangeably, Blender does not. It assigns different functions to each set. If you're using a laptop keyboard without a separate numeric keypad, this might cause some difficulty. You'll need to use your function key to do some things. It is possible to indicate to Blender the type of keyboard you are using, but we strongly recommend you use a standard external keyboard if you use a laptop for these tutorials as it will make your studies and usage of Blender much more straightforward and enjoyable.
This book often assumes your keyboard has a numpad. If yours doesn't, consult the tutorial on Non-standard Input Devices for alternative ways to access the numpad's functions.
|Notation||Action or Key|
|(press and hold) the Alt (Option) key|
|(press and hold) the Command or Super key (On a Windows keyboard, the key bearing the Windows logo; on a Macintosh, it bears the word command.)|
|(press and hold) the Ctrl (Control) key|
|(press and hold) the Fn (Function) key (generally found only on laptops)|
|(press and hold) the Shift key|
|(press) the Enter (Return) key (on the main keypad)|
|(press) the Esc (Escape) key|
|through||function keys F1 through F12 (often in a row along the top of the keyboard)|
|(press) the space bar (usually unmarked)|
|(press) the Tab key|
|through||the letters (on the main keypad)|
|through||the numerals (above the letters) on the main keypad|
|through||the numerals on the numpad|
|, , , , , , and||other keys on the numpad|
|(press) the Delete key (not!)|
|(press) the down Arrow key (not!)|
|(press) the left Arrow key (not!)|
|(press) the right Arrow key (not!)|
|(press) the up Arrow key (not!)|
Combinations that involve holding down a key while performing another action are written with a plus sign (+). Thus:
- + means to while holding down
- + + means to while holding down both and .
Blender uses three mouse buttons and the scroll wheel, if you have one. If your mouse only has one or two buttons, consult the tutorial on Non-standard Input Devices for alternative ways to access the functions assigned to these buttons.
|Notation||Action or Button|
|click with the Left Mouse Button|
|click with the Right Mouse Button|
|press down on (don't turn) the scroll wheel or Middle Mouse Button|
|SCROLL||turn the scroll wheel in either direction|
Mouse and keyboard actions are often combined.+ means to click while holding down .
Blender uses both pop-up and pull-down/pull-up menus. Many menus have sub menus (menus that are reached via another menu). If a menu item displays a triangle, that means it leads to a sub menu.
You can move through items in a menu by:
- moving the mouse pointer up and down
- pressing and
You can enter a sub menu by:
- moving the mouse pointer to the right
You can leave a sub menu by:
- moving the mouse pointer to the left
To initiate a menu action, you can:
You can escape from a menu by:
- moving the mouse pointer away from the menu
For each menu, Blender remembers your last choice and highlights it for you the next time you enter the menu.
Menu notation is fairly self-explanatory.
+ Mesh → UV Sphere
- Press Shift+A
- In the menu that pops up, move through the items until Mesh is highlighted
- Enter the Mesh sub menu
- Move through the items until UV Sphere is highlighted
- Press Enter or click the left mouse button to initiate the action
- the Blender Manual page on "keyboard and mouse" at http://wiki.blender.org/index.php/Doc:Manual/Interface/Keyboard_and_Mouse
Non-standard Input Devices
This module is applicable only to users with non-standard input devices. If you have both:
- a three-button mouse
- a keyboard with a numpad,
you can skip this module.
Keyboards lacking a numpad
Most modern laptops have a pseudo-numpad, a set of keys in the main keypad which double as a numpad. The keys typically used for this purpose are:
When used as a pseudo-numpad, these keys typically act as the following keys from a true numpad:
The numpad functions of these keys can often be toggled withor on PCs or with on Macs. Alternatively, you can often temporarily activate the numpad behavior by holding down .
If your keyboard has the alternate labellings but you don't know how they work, consult your laptop owner's manual.
As a last resort, you can use the "Emulate Numpad" feature of Blender. This will allow you to use the normal numeric keys as if they were numpad numerics. Instructions for enabling this feature may be found in the "User Preferences Windows" module.
Blender uses the numeric keypad quite a bit. If you envision using your laptop for this kind of work, it may be worth investing in a USB Numeric Keypad. On eBay, prices for simple external numpads start around $10 USD.
For single-button mouse users, make sure that Input for Blender 2.79 (under "User Preferences" on the left-most drop-down menu) → Emulate 3 Button Mouse is enabled.
On many computers with two-button mice,can be emulated by simultaneously clicking and . On Windows machines you'll need to enable this in the mouse settings in the Control Panel. On a Mac, open the Keyboard and Mouse preference pane and enable Use two fingers to scroll. Alternatively, by selecting Emulate 3 Button Mouse under User Preferences, can be emulated by simultaneously clicking and .
Recent IBM Thinkpad laptops allow you to disable the 'UltraNav' features of the middle mouse button in order to use it as a 'normal' third button. Alternatively, some laptops allow areas (called gestures) on the movement pad to act asor , and these can be set up in the Control Panel in the Mouse Pointer options, selecting gestures and editing features there.
|the Mouse Button|
|+||Apple key + the Mouse Button|
|+||Option (Alt) key + the Mouse Button|
While Mac OS X natively uses both the+ and + to emulate , recent Blender releases for Mac OS X use only + for this purpose. This behavior is documented in the OSX Tips file that comes with the Mac version. You can also set the mouse to sense a right-click in System Preferences.
Note also that in the new, "unibody" design, the mouse button is under the trackpad, and the shortcut foris clicking with two fingers simultaneously, which can be enabled in the System Preferences.
Many laptops have smart pads. Smart-pads can use gestures to give the effect of. The default for an Elan® Smart-Pad is two-finger tapping equivalent to clicking a . Dragging two fingers is the same as turning a mouse wheel.
To get the effect ofin a viewport, drag your pen around while holding down the key.
Operating System-specific Issues
This tutorial covers user-interface issues that are specific to particular operating systems or window managers. Read the section that applies to your computer; you may skip the rest.
+ is used for changing the angular view on two angular axes of the 3D View window, if + moves the current window, then there's a conflict with your window manager. You can resolve the conflict or use + + or instead. (Also, you may have activated Compiz->Rotate Cube. Default configuration for rotating the Cube is also + + ; you may have to change this binding to an alternative configuration.) If you are running KDE this can be resolved by: on the title bar of the main Blender window → select Configure Window Behavior → go to Actions → Window Actions → in the Inner Window, Titlebar and Frame section → select the Modifier key to be and set all the select boxes beneath it to Nothing. An alternate method within KDE might be to click on the title bar of the main Blender window; then select Advanced → Special Application Settings... → Workarounds and then click Block global shortcuts with Force selected and checked.
In Gnome, Click System → Preferences → Window Preferences. Look for the last three options Control, Alt and Super. Select Super. Or in Xfce, click Whisker → Settings → Window Manager Tweaks, and in the Accessibility pane, change Key used to grab and move windows to Super. Now you can press and holdor to drag windows around, and use and as normal.
Under KDE,+ through + are by default configured to switch to the corresponding one of the first four desktops, while + brings up Plasma settings. You can change these in System Settings.
Alternatively you can suppress global shortcuts while inside blender by adjusting the kwin rules for this application, which you can access with aclick on the title bar of the window and pressing more actions->add program rule.
You'll want to disable the Find Pointer functionality in Gnome, which will impair your ability to use certain functions such as Snap to grid and the lasso tool. If your mouse pointer is being highlighted when you press and release, go to: Mouse in Gnome's Desktop Settings and uncheck the box Find Pointer.
As of Ubuntu versions prior to about 09.10 (“Karmic Koala”), there was a known incompatibility between Blender and the Compiz Fusion accelerated (OpenGL) window manager used in Ubuntu. By default, Compiz Fusion is enabled in Ubuntu, causing the problems to manifest themselves in Blender as flickering windows, completely disappearing windows, inconsistent window refreshes, and/or an inability to start Blender in windowed mode.
The fix for this is simple. Install compiz-switch (might be in universe). Go to Applications → Accessories → Compiz-Switch. This will disable compiz temporarily. Do the same to turn compiz back on when you're done using Blender.
This is no longer needed for current releases of Ubuntu.
Mac OS X
You may need to pressin order to use the through keys.
To expand a section in Blender, you would usually press+ . On a Mac, if “Spaces” is enabled, you may have to use + + .
Two Ways to Launch Blender
Blender requires a console for displaying error messages, so if you launch Blender by means of an icon, two windows will appear: the graphical user interface plus a console window. Closing either window will terminate Blender. These windows are indistinguishable in the Windows taskbar in versions of Windows before Windows 7, which leads to confusion. Also, launching this way does not provide any way to pass command-line arguments to Blender.
Launching Blender from a command prompt is extra work, but it overcomes these issues:
- Start → Run...
- enter cmd
- enter cd c:\Program Files\Blender Foundation\Blender
- enter blender
Blender version 2.6 onwards doesn't have this problem, and hides the console window by default. You can show it by clicking Window > Toggle system console
Pressing StickyKeys, an accessibility option which alters how the computer recognizes commands. If a StickyKeys dialog box appears, you should the "Cancel" button.five times in a row may activate
If you don't need the accessibility features, you can disable sticky keys:
- Start → Control Panel (OR search for "Accessibility Options" on the Start menu/Search)
- double-click on Accessibility Options (Ease of Access Center in Windows 10)
- the Keyboard tab
- for each of the options StickyKeys, FilterKeys, and ToggleKeys:
- clear the Use … checkbox
- the Settings button
- uncheck the Use Shortcut checkbox in the settings
- the OK button for the settings
- the OK button for Accessibility Options/Ease of Access Center.
Multiple Keyboard Layouts
On systems with multiple keyboard layouts, pressing+ can alter the layout. (For instance, it might change from QWERTY to AZERTY or vice versa.) Because of this issue, Noob to Pro avoids + hotkeys.
If you find your keyboard layout altered, press+ again to change it back.
You can also disable the hotkey:
- Start → Control Panel
- double-click on Regional and Language Options
- the Languages tab
- the Details button
- the Key Settings button
- the Change Key Sequence button
- uncheck the Switch Keyboard Layout checkbox
- the OK button
- Input method editor keyboard shortcut (CTRL+SHIFT+0) switches the input language in Vista — Microsoft Support Knowledge-Base
- StickyKeys at Wikipedia.
Blender User Interface
Here's a preview screenshot of Blender's interface.
For those familiar with older versions of Blender, this will look very different. The redesign makes it much easier to find things.
For a detailed rationale explaining the redesign, read this.
Why Doesn’t It Follow UI Conventions For [Insert OS Of Choice Here]?
Blender follows its own user interface conventions. Instead of making use of multiple windows as defined by your particular OS/GUI, it creates its own “windows” within a single OS/GUI window, which is best sized to fill your screen. Many people accustomed to how applications normally work on their platform of choice, get annoyed by Blender’s insistence on being different. However, there is a good reason for it.
The essence of the Blender UI can be summed up in one word: workflow. Blender was originally created by a 3D graphics shop for their own in-house use. Being a key revenue engine for them, they designed it for maximum productivity, speed and smoothness of operation. That means avoiding “bumps” that slow down the user. For example, windows never overlap, so there’s no need to keep reordering them. You don’t have to click in a window to make it active, just move the mouse. There is a minimum of interruption from popups asking for more information before performing some action. Instead, the action is immediately performed with default settings, which you can adjust afterwards and get immediate feedback on the results.
Blender may not be “intuitive” to start learning, in that you cannot simply sit down in front of it and figure out things on your own, especially from a position of knowing nothing at all. But once you have picked up some basic conventions, you will find it starts to make sense and then you will be free to experiment and discover things on your own.
Why Doesn’t It Prompt To Save Changes?
Most modern applications will ask for confirmation if you try to close a document that has unsaved changes. Blender is frequently criticized for not doing so.
But think about it. What constitutes an “unsaved change”? Are switching tools or adjusting the window layout changes worth saving? In Blender’s case, the answer is “yes”, because all that is part of the document state to be restored upon opening. So Blender would have to prompt for confirmation practically every time you closed a document or quit Blender.
Instead, Blender always saves changes when it closes, to a file called 'quit.blend'. The next time you use Blender, simply select File → Recover Last Session and you can resume right where you left off.
However, as of Blender version 2.79, you are warned on exit when there are unsaved changes. You can change this behaviour in User preferences / Interface / Warnings / Prompt Quit.
Blender Windowing System
|Applicable Blender version: 2.69.|
The Blender user interface may appear daunting at first, but don't despair. This book explores the interface one step at a time.
In this module, you'll learn about Blender windows:
- recognizing windows and their headers,
- the different types of windows,
- how to activate and resize windows,
- how to split and join windows.
You'll also practice launching and leaving Blender.
An Interface Divided
Blender's user interface is divided into rectangular areas called windows (or sometimes, areas). The overall arrangement of windows is called a workspace.
If you haven't already launched Blender, go ahead and do so. You should soon see something that resembles the following.
Blender has had some major changes to its user interface (UI) since version 2.4x. Some of these changes include moving buttons and changing the space bar hot key from the “add menu” to the “search menu” (+ is now the "add menu” hot key). This is important to know when trying to follow tutorials.
Other changes include the addition of the tool bar and window splitting widget. The shelf widget (indicated by a plus sign) opens hidden tool shelves. The object tool shelf can be toggled on and off by pressing. The properties tool shelf can be toggled on and off by pressing the . The split window widget allows you to split and join windows. Blender 2.69 is shown below.
Did you find all five headers?
Every Blender window has a header. A header can appear at the top of the window, at the bottom of the window, or it can be hidden. Let's take a closer look at the headers.
If you click withon the header, a menu pops up which lets you move the header (to the top if it’s at the bottom, or vice versa), or maximize the window to fill the entire workspace:
To hide the header completely, move the mouse to the edge of the header furthest from the edge of the window (i.e. the top edge of the header if it is at the bottom of the window, or vice versa); it will change into a vertical double-headed arrow. Now click with . Click this with to bring the header back.and drag towards the window edge, and the header will disappear. In its place, you will see the following symbol appear at the corner of the window:
Blender has many types of windows (there are 16 of them in Blender 2.69) and a Console for the Python programming language. You've just encountered the Info, 3D View, Properties, and Outliner windows. The rest will be introduced as needed in later modules.
Every window header in Blender has an icon at the left end to indicate the window type. For instance:
If you Keystrokes, Buttons, and Menus Notation module.)on the icon, a menu will pop up. (If you don't know what means, please review the
Any window can be changed to any type. Blender doesn't mind if there are multiple windows of the same type.
The workspace layout is saved along with the document. Anybody subsequently opening the document will see the last-saved layout.
If you've changed any window's type, please change it back (or reload the factory settings with File → Load Factory Settings) before continuing with this tutorial.
The Active Window
The active window is the one that will respond if you press a key. Only one Blender window is active at any given time.
The active window is usually the one containing the mouse pointer. (Blender uses a "focus follows mouse" user interface model. When a hotkey fails to work as expected, it is often because the mouse pointer has strayed into a neighboring window.) To change the active window, simply move the mouse pointer into the window you wish to activate.
Practice changing the active window by moving your mouse between the 3D View and the Timeline windows. The Timeline window is directly below the 3D View header. At this point, it's worth mentioning that the header for the 3D View window and Timeline window is at the BOTTOM of its own window instead of the top as the name "header" implies.
When a window becomes active, its header gets brighter.
Resizing windows is easy.
Dragging on a Border
Whenever you increase the size of one window, you decrease the size of another. That's because Blender has a non-overlapping window interface: unlike many other programs, it does not permit windows to overlap. Neither does it move windows; it just resizes them. If you find that you cannot increase the size of a window (e.g. the Info window) any further although there seems to be enough space to do so, it may be because you decreased the size of another window (e.g., the Outline window) to its minimum size (i.e, just the heading).
Maximizing a Window
Another way to resize a window is to maximize it. When Blender maximizes a window, it makes the window as large as possible. The previous window configuration is saved.
- To maximize the active window, press + , + or + . On a Mac, if “Spaces” is enabled, you may have to use + + .
- When a window is maximized, use + , + or + to restore the previous (unmaximized) window configuration.
Practice maximizing and un-maximizing the 3D View and Timeline windows.
If you are running a version of Blender before 2.57, you cannot maximize a User Preferences window.
You will notice that the 3D View window (the largest window in the screenshots above) has several buttons down the left side. This rectangular portion is called the Tool Shelf. This is like a window within a window - you can drag the boundary between it and the main part of the 3D View to resize.
Too Much To Fit
If a window or shelf contains too much information to fit within its display area, scrollbars will appear along the bottom or right edge. You can scroll the contents by dragging these with; alternatively you can drag with directly within the contents.
A window header may also contain more than fits within its displayable area. There is no explicit visual clue for this (though some of the widgets at the right edge might not be visible), but if that happens, you can drag sideways within the header withto scroll its contents.
Splitting And Joining Windows
At the top right and bottom left of every window, you will see something like this: . If you move the mouse over the icon, you will see the pointer turn into a cross. At that point, you can do one of the following by clicking and dragging with :
- Split the window into two copies horizontally by dragging horizontally away from the edge.
- Split the window into two copies vertically by dragging vertically away from the edge.
- Join the window to the adjacent one horizontally (getting rid of it and taking over its space) by dragging towards it.
- Join the window to the adjacent one vertically (getting rid of it and taking over its space) by dragging towards it.
Of course, the last two are only possible if there is in fact another window in that direction. Note: you can only join windows horizontally that are the same height, and windows vertically that are the same width.
The Default Workspace
If you look at the above screenshot of the default workspace, you will see the following window types:
- The menu bar at the top (outlined in green) is actually a window, called Info . In previous versions of Blender, you could resize this to reveal the User Preferences, but in 2.5x they have been moved to their own window type. Instead, all you can see here if you enlarge the window are some debug messages, which may be removed in a future version of Blender. As of 2.70, the debug messages are still present in this menu.
- The largest window on the screen is the 3D View . This is where you work on your model.
- The Properties window is the tall area on the right; this is where most of the functions are located for performing operations on models, materials etc. In previous versions of Blender this was called the Buttons window. Over time, it evolved into a disorganized area that made it difficult to find things. It has been cleaned up significantly in 2.5x. Note that it defaults to a vertical layout, rather than the horizontal one of previous versions. The new design prefers a vertical layout, which better suits today’s widescreen monitors.
- The Outliner (at the top right) gives you an overview of the objects in your document. As your models get more complex, you will start to appreciate the ability to quickly find things here.
- The Timeline (across the bottom) becomes important when you’re doing animation.
The default layout may not be optimal. For example, if you’re doing a static model or scene, not an animation, you can get rid of the Timeline. If you’re doing heavy script development, you’ll probably want the Console available to try things out. And so on.
Selecting from this menu lets you quickly switch between various predefined workspace layouts, tailored to various workflows. Try it and see. You can return to the default layout by selecting “Default” (but note that any changes you make to the layout are immediately associated with the name being displayed here). The menu has a search box at the bottom. Typing text here will restrict the menu to showing items containing only that text. It might not appear to have much use, but in a complicated project that needs dozens of different layouts, the search function could become very useful indeed!
The name of the currently selected item appears to the right of the menu icon. In the illustration above, this is "Default". Blender allows you to rename the current menu item by clicking on it with theand typing a new name, so take care not to do so unless you actually want to rename the menu item. For example, if you replace the name "Default" with "MyDefaults", you will subsequently see that "MyDefaults" appears in the list of menu items.
Note also the “+” and “X” icons to the right of the menu; clicking “+” creates a new entry which is a duplicate of the last-selected entry, while clicking “X” gets rid of the currently-selected entry. You will see these conventions appear consistently in menus elsewhere in Blender’s new, revamped interface.
One Document At A Time
Blender can only work with one open document at a time (this does not apply to blender 2.79, which allows multiple instances of blender to run concurrently). To save changes to the current document, select one of the Save options from the File menu (or press+ to save under the last-saved name). To open a new document (actually load a copy of your last-saved user preferences), select “New” from the File menu (or press + ), and select “Reload Start-Up File” from the popup that appears, but be aware this will not automatically save any changes to the previous document.
A scene is like a separate Blender-document within-a-document. Different scenes within the same document can easily share objects, materials etc. You can define them once and make different renderings and animations from them. You create, delete and switch scenes using the scene menu in the info header. A new document starts by default with just one scene, called “Scene”.
To exit Blender:
- If there's a tool active, press to exit the tool.
- Press + . This brings up an OK? menu.
- Confirm Quit Blender by clicking or pressing .
In versions before 2.79, Blender will not prompt you to save your work. However, you can easily pick up where you left off by using File → Recover Last Session.
- YouTube video on Splitting and Joining Windows in 2.49 at http://www.youtube.com/watch?v=uYb1j8X-ulc
- YouTube video on Splitting and Joining Windows in 2.59 at http://www.youtube.com/watch?v=mGK1gwFhx9M
- the Blender Manual page on "window types" at http://wiki.blender.org/index.php/Doc:Manual/Interface/Window_types
- the Blender Manual page on "changing window frames" at system/Arranging frames http://wiki.blender.org/index.php/Doc:Manual/Interface/Window system/Arranging frames
User Preferences Windows
|Applicable Blender version: 2.80.|
In this module, we'll take a closer look at the Blender Preferences window.
Accessing Blender Preferences
To open the Blender Preferences window click Edit → Preferences...
In Blender 2.79, you will find it under File → User Preferences...
Configuring Your Preferences
In order to get to modeling and rendering sooner, this tutorial will cover only a few of the many user-settable preferences.
If you ever need to restore Blender to its factory settings, click File → Defaults → Load Factory Settings
Save & Load → Auto Save
As the name suggests, Auto Save automatically saves the current .blend after a specified period of time. The settings are:
- Auto Save Temporary Files: This enables/disables the auto save feature.
- Timer (mins) slider: This specifies the time in minutes between each auto save.
System → Number of Undo Levels
Next we'll look at the undo settings. By default, Blender remembers your last 32 actions and allows you to undo them one at a time by pressing
Input → Numpad Emulation
Blender uses numberpad keys (such as) to control the 3D View and ordinary numeral keys (such as ) to change layers. If you are working on a laptop or if you find the numberpad inconvenient, you can select Emulate Numpad to reassign the 3D View controls to the ordinary numeral keys.
- The Blender manual pages on Preferences
- The tutorial on Non-standard Equipment describes other workarounds for numpad issues.
|Applicable Blender version: 2.67.|
The Properties window is where you will find most of the functions that Blender can perform with objects and materials, animation, rendering, etc. It is the area where you will see the greatest number of changes from earlier versions of Blender (in which, it was called the Buttons window). Hopefully you’ll agree the new layout makes it much easier and quicker to find things!
In the header of the Properties window, you will see a row of buttons that looks like this: The actual icons will vary depending on the type of object selected in the 3D view. In the default layout, the Properties window may be too narrow to show the entire row, in which case you can widen the window, click drag across the buttons with to scroll the button row, or use your mouse wheel within them. Each of these buttons gives you access to a different context, or subsection of the Properties settings. Unlike older verions of Blender, there are no more “subcontexts” — no additional buttons will appear in the header when you click any of these.
Render Context 
Here we find the settings that control overall rendering of the final images, i.e. what resolution to use, output format, performance, post processing, etc.
Render Layers Context 
Additional settings that offer finer control over rendering of the final images: which scene layers to render, which separate parts (passes) of the rendering process to actually perform, and how to group them into render layers (not to be confused with the scene layers) for input into subsequent compositing.
In versions of Blender prior to 2.67, these settings were combined into the Render Context.
Scene Context 
Contains settings for colour management, choosing which camera to use for rendering, and units and gravity settings for physical modeling.
You can also select another scene to be a “background” for this scene. That is, all renders of this (foreground) scene will also include the contents of the background scene, as though they had been copied into this scene. While the background appears in the 3D viewport when editing this scene, none of its contents are editable, or even selectable; that has to be done in the background scene itself.
World Context 
Settings that govern the environment in which the model is rendered. e.g. background sky color, mist and star settings, lighting etc.
Object Context 
Settings that apply to all types of objects. e.g. overall transformations, layer assignments, grouping etc. The settings shown here (and any changes made) apply to the last object selected. This is also the case for the following object-specific contexts.
Object Constraints Context 
These settings limit the motion of the object for animation purposes. The limits can also be tied to the motion of other objects in various ways.
Object Modifiers Context 
Settings for applying modifiers to the object geometry. These make changes to the geometry that only take effect at rendering time. Note: lamps, cameras and empty objects cannot have modifiers.
Object Data Context 
Settings specific to the type of object, e.g. mesh vertex groupings, text font, lamp settings, camera settings, etc. This is reflected in the icon, which changes according to the type of object selected.
Material Context 
The material settings for an object control its appearance, e.g. its colour, whether it has a shiny or dull surface, how transparent it is, and so on.
The chosen rendering engine — Blender Internal (the default), Blender Game, or Cycles — will impact the choices available for material and texture settings.
Texture Context 
The texture settings specify patterns that break up the uniform appearance of a material. These patterns can affect the colour of the material, give it a rough surface, or modify it in other ways.
Particles Context 
An object can be set to emit particles, like smoke, flames or sparks. The concept of “particles” (and the underlying algorithms) also includes the generation of hair or fur. Particles can be entirely custom objects, to produce effects like blades of grass interspersed with flowers in a field, water droplets on a wet surface, or even scatterings of entire buildings to make up a large cityscape!
Physics Context 
Settings that control how the object reacts to forces similar to objects in the real world, e.g. whether it behaves like a rigid body that keeps its shape but can be knocked around, something soft e.g a pillow, or a flowing liquid.
Where Did The Old Stuff Go?
3D View Windows
|Applicable Blender version: 2.70.|
The 3D view only shows an approximation of the final appearance of the scene. The overall geometry should be correct, but don’t expect accurate rendition of materials, textures, lighting etc, since that can be very time consuming. The 3D view is designed to respond to your actions at interactive speeds. There are additional view options (wireframe, hiding etc) that make it easier to see which parts of the model you’re working on, have no effect on the final render. You can change your viewpoint at any time (which will be essential while working on your model/scene), while the viewpoint of the render is controlled by the camera position.
In this module, you'll learn:
- to recognize 10 things commonly seen in viewports
- to tell which mode Blender is in
- how to change viewport options and viewpoints
- how to position the 3D cursor
You'll also learn the fundamentals of:
- visibility layers
The Viewport and its Contents
Aside from its header, the remainder of a 3D View window is its viewport. You use viewports any time you need an up-to-date view of the scene you're working on.
Viewports are busy places. Go on a scavenger hunt and see what you can find in a simple viewport.
- Launch Blender.
- Just so we're all looking at the same scene, load the factory settings using File → Load Factory Settings.
- Confirm the “Load Factory Settings” popup with (or ).
- If the NumLock indicator on your keyboard is unlit, press so that numpad hotkeys will work properly.
(If you're unsure what the Keystroke, Button, and Menu Notation module.)means, please review
You should see something like this:
A Virtual Scavenger Hunt
Look at the default scene and find the following eight items:
- In the Center
- This is the default cube, your first Blender object!
- This is not an object (part of your model/scene), but part of Blender’s user interface for manipulating objects. It is the manipulator, also known as the 3D transform widget.
- The arrows represent the directions of the X, Y and Z axes of the currently chosen transform orientation coordinate system. Initially this is the global coordinate system.
- The circle represents the center of the selected object (the cube).
- If you don't know what the "global coordinate system" is, please review the module on Coordinate Spaces in Blender.
- This is not an object. It is the 3D Cursor, which indicates where newly-created objects will appear in the scene.
- The cursor is similar to the insertion point in a text editor, which indicates where new text will be inserted in a document.
- In the Lower Left Corner
- This is not an object. It is the mini axis, and its orientation matches that of the global coordinate system, with the usual conventions: red for X, green for Y and blue for Z. Think of it as a little compass, reminding you which way is left/right, front/back and up/down.
5. The notation "(1) Cube"
- This is not an object. It is object info, indicating that:
- You're viewing the first frame of an animation.
- The current or most recently selected object is named "Cube".
- In the Upper Left Corner
6. The notation “User Persp”
- This is not an object. This tells you which mode the viewport is in. The first word will change if you select one of the perfect views or the camera view (see below), otherwise it just says “User”, and the second word is “Persp” or “Ortho” to indicate whether this is a perspective or orthographic view.
- To the Right of Center
- This represents a lamp, a light source for the scene. (It is an object.)
- This represents a camera, a viewpoint that can be used for rendering. (It too, is an object.) The camera is looking at the base of the pyramid. The solid triangle attached to one side of the base is to remind you which way is up in the image that the camera takes.
- On a small display, the camera might initially lie outside of the viewport and thus be invisible. In that case, SCROLL to zoom out until it becomes visible.
9. A dark gray background, divided into squares by lighter lines. This is the grid floor, which you can (but don’t have to) use as a ground plane for positioning your models.
- Each grid square is one blender unit (or BU) on a side. A BU can be whatever you wish, e.g. an inch, a centimeter, a mile, or a cubit. Blender lets you choose your scene scale in the Scene tab of the Properties Panel.
10. Three mutually perpendicular coloured lines associated with the grid floor: the red and green ones lying horizontally in the floor and the blue one running vertically. These are the global coordinate axes for orienting your scene. Red is the X-axis, green the Y-axis, and blue the Z-axis.
- In Blender 2.67a, you can't see the blue line for Z-axis here, but you can see it in Front or Side view.
Blender has many modes, i.e. settings that affect its behavior, and this is especially true of the 3D View window.
Sometimes it's not obvious which mode is active. This leads to mode errors where Blender will do something you didn't expect because you thought it was in one mode and it was actually in another.
The function performed by a hotkey or mouse button can depend on:
- what mode the user interface is in,
- whether the keyboard is in NumLock mode,
- which window is active,
- the mode the active window is in,
- which item or items are selected,
- whether you've initiated a hotkey sequence.
It helps to recognize the common modes and how to get out of them.
Object Mode vs. Edit Mode
The 3D View windows are normally in Object Mode. In this mode:
- The mouse pointer is the default arrow normally used on other programs.
- is used to select objects in the scene.
- In versions 2.8 and above Use to select objects in the scene
If there are objects in the scene, you can get into five other modes:
- Edit Mode: used to edit the shapes of objects
- The mouse pointer is a thin inverse-video cross.
- is used to select vertices, faces or edges of the current object.
- Press to enter/exit this mode.
- Sculpt Mode/Vertex Paint/Texture Paint/Weight Paint
- The mouse pointer is now a thin, orange (white in Texture Paint) circle.
These modes are also indicated by a menu in the 3D View header. You can use this menu to change modes.
These modes are a setting shared by all 3D View windows. In other words, when you change the mode in one window, any other 3D View windows change mode also.
The options in this section only affect 3D View viewports. They do not affect renders.
Solid vs. Wireframe
By default, the 3D View window draws objects using the Solid drawtype, in which surfaces are opaque. To toggle between Solid and Wireframe drawtype (edges only, no faces) for a particular viewport:
- Activate the 3D View window
- Press .
Alternatively, you can choose these and other drawtypes from the "Viewport shading" menu in the 3D View window header.
Orthographic vs. Perspective
By default, viewports draw orthographic views. To toggle a viewport between orthographic and perspective views:
- Activate the 3D View window.
- Press .
Note this perspective versus orthographic setting for the 3D viewport is completely separate from the similar setting in the camera properties. The former takes effect while you’re working on the model, the latter when you render.
So why have a separate setting for the 3D view? Because certain aspects of modelling are easier in one view than another. If the final render will be using perspective, then showing perspective in the 3D view naturally gives you a better idea of how the final render will look. But perspective foreshortening can sometimes make it hard to ensure the model has the proper shape, which is why there is the option to switch to orthographic view.
Changing Your Viewpoint, Part One
Each viewport has a viewpoint, which takes into account:
- the location of the viewer in the 3D scene (There doesn't need to be an object at that location.)
- the direction the viewer is looking
- the magnification (or zoom factor) used
Changing your viewpoint allows you to navigate your way through a 3D scene.
We'll start with three very basic techniques:
- Orbiting/View Rotation
- Perfect Views.
Additional techniques will be covered later in this module.
Blender offers several ways to zoom in and out:
- Use SCROLL
- Click and drag vertically with + .
- Use and to zoom in and out in small increments.
Note the following limitations of Blender's zoom feature:
- If the viewport is in orthographic mode, Blender zooms as if looking through a telescope. You can increase the magnification, but the viewpoint's location doesn't change. For this reason, you cannot zoom into or through objects in orthographic mode.
- If the viewport is in perspective mode, Blender zooms to the center of the viewport. The viewpoint can pass through objects, but can't pass beyond this point, no matter what you do. Zooming only gets slower and slower and slower. If the center of the viewport is somewhere you don't expect, zooming may appear to be broken.
Orbiting and View Rotation
Let's fly around the default cube, viewing it from different angles. In this way you'll see that it really is a cube, centered on the origin, half above the X-Y plane and half below it.
- Activate the 3D View window by placing the mouse pointer inside it.
- Now you can:
- Click and drag with to orbit freely around the center of the view.
- Use SCROLL to rotate the viewpoint vertically around the center of the view. + +
- Use and to rotate the viewpoint vertically around the center of the view in 15-degree increments.
- Use SCROLL to rotate the viewpoint around the Z axis. + +
- Use and to rotate the viewpoint around the Z axis in 15-degree increments.
If this is all very confusing for you, don't worry! You'll learn as you get more experience.
When you are finished flying around the cube, you can restore the original view by reloading the factory settings with File → Load Factory Settings.
The center of the viewport is not marked, i.e. it's difficult to tell where it is. This can cause unexpected behavior during rotation.
It's often useful to get a perfect view of a scene, i.e. to view it along one of the main axes, with the other two main axes oriented up-down and left-right.
|Hotkey||View||Axis Pointing Right||Axis Pointing Up|
The following screenshot shows all three perfect views plus camera perspective for the Suzanne primitive:
This layout is used so often, it has a keyboard shortcut: (+ + ).
Positioning the 3D Cursor
Positioning the 3D cursor is a very basic operation, yet one that many beginners find challenging. It touches on an issue common to all 3D graphics software: "How do you specify points in a 3D scene when we can only see two dimensions at a time?"
- Go into either Object Mode or Edit Mode.
- Move the mouse pointer to the desired position (in any viewport).
- Click .
|This technique will fail if the 3D manipulation widget is enabled and your desired position is too close to it. Clickingon or near the widget (the white circle with the colored arrows) will initiate a transform operation; the object's outline will turn white and the mouse pointer will begin dragging the object around. If this happens, press to cancel the transform operation.|
|Clickingin a viewport can only reposition the cursor in two out of three dimensions. (The cursor's projected distance along the central line-of-sight remains unchanged.) For this reason, any time you reposition the cursor this way you should immediately verify its position using a different viewpoint.|
Challenge #1. Using only tools presented thus far, try positioning the 3D cursor on the virtual camera.
When you're done, check your work by orbiting the camera.
Perhaps you thought you were done when you clicked on the camera. But the moment you changed your viewpoint, you probably found that the 3D cursor was actually behind (or in front of) the camera.
- Try positioning the cursor in two different perfect views.
- Use orthographic, not perspective, view.
Challenge #2. Using only tools presented thus far, try repositioning the 3D cursor at the origin (that is, at the center of the cube).
As before, check your work by orbiting the cube. Don't spend too much time on this.
More Ways to Position the Cursor
Here's an easy way to position the cursor at the center of an object:
- Make sure Blender is in Object Mode, with the object selected.
- Move the mouse pointer to any 3D View window.
- Snap the cursor to the selected object using either:
- + → Cursor to Selected
- Object → Snap → Cursor to Selected
Here's 2 easy ways to relocate the cursor to the scene's origin (0, 0, 0):
- Move the mouse pointer to any 3D View window.
+ to reset the cursor to the origin.
- Note that this also changes the view location, meaning that when you zoom in, you won't zoom in to the scene origin.
- A better way is to click Object → Snap → Cursor to Center
- You can also do this by + → Cursor to Center.
Changing Your Viewpoint, Part Two
Now you'll learn some additional techniques for obtaining the view you want:
- Jumping to the camera's viewpoint
- Zooming in on a selected area
When you orbited the cube, the viewpoint's position and direction both changed at the same time. You also can shift the viewpoint up-down or left-right without changing its direction. (This is similar to the side-scrolling effect in the classic Mario and Sonic video games.)
This is called panning, and it's an important skill to master. Try it now:
- Activate a 3D View window by placing the mouse pointer inside it.
- Now you can:
- Use SCROLL to pan up and down. +
- Use + and + to pan up and down in small increments.
- Use SCROLL to pan left and right. +
- Use + and + to pan left and right in small increments.
- Click and drag with
You will likely find this to be a distraction in some cases. To move the viewpoint position back to the center, snap the cursor to the center, then click View → Align View → Center View to Cursor. You could also snap the cursor to the center then press
In versions ≥2.74 you can also use+ to center the view to the cursor.
When you zoom or rotate the view, you always zoom or rotate around the center of the view.
To make sure everything in your scene is visible:
- Press .
To center the view on an arbitrary point:
- Move the 3D cursor to the point of interest.
- Verify the cursor position from a second viewpoint.
- Press + to center the view.
To center the view on an object in the scene:
- Make sure Blender is in Object Mode.
- Zoom out until the object is in the viewport.
- If any objects are selected, use (or Select → Select/Deselect All) to deselect them.
- Select the object of interest by clicking on it.
- Press to center the view.
Jumping to the Camera's Viewpoint
To see the scene as the virtual camera sees it, press. Afterwards, you can rotate, pan, and zoom normally, but the virtual camera will not follow. To go back to your previous view, press again. (In the latest versions of Blender, the virtual camera can be made to follow all the changes made in viewpoint while in camera view by checking the option "Lock Camera to View" on the Transform panel. Hit on your keyboard to bring up the transform panel. To disable this option uncheck "Lock Camera to View.")
Zooming into a Selected Area
Suppose you want to get an extreme closeup of a particular area. Because there's no center mark on the viewport, you might have to pan and zoom several times to get the desired view.
The shortcut for zooming to an area is:
- Activate a 3D view window that contains the area of interest.
- Press + . A crosshair appears in the viewport.
- Click and drag with to draw a rectangle around the area of interest.
- When you release , the viewport will zoom in on the area you selected.
You can also change your viewpoint in the 3D view by “walking” or “flying” through it. To activate this, press+ . By default in Blender 2.70, this puts you in “walk” mode. Earlier versions only offered “fly” mode. (In Blender 2.70 and later, you can choose which one you prefer in User Preferences, under the Input tab.)
In both modes, helpful prompts appear in the header of the 3D view window to remind you of the key functions while the mode is in effect. When you have reached the position and orientation you want, pressor or to end the navigation mode and stay there, or or to abandon the navigation mode and be teleported immediately back to your original position and orientation. (In 2.77+, pressing will teleport you to where the cross hairs point towards.)
In this mode, you move the mouse to turn your view up/down/left/right, and, , and or the corresponding arrow keys to move forward, left, back or right, and and to move up or down respectively. Hold a movement key down to keep moving. Movement stops as soon as you release it. Pressing will “teleport” you close to whatever objects lie within the crosshairs at the centre of the view.
You can also useto turn on gravity. Make sure there is a floor or other object under you to land on! With gravity on, you can no longer use the vertical movement keys, but you can use to make jumps. Press again to turn gravity off.
In this older mode, moving the mouse to change the view works the same as in Walk mode, but the above direction keys (, , , , , and the arrows) apply “thrust” in the respective directions, so you keep moving after releasing the key. Press the key repeatedly to increase your speed in that direction, or press the key for the opposite thrust direction to reduce your speed. You can roll the mouse wheel up to apply forward thrust, or roll it down to apply backward thrust.
Your current velocity vector automatically changes direction with you when you turn. Thus, you can apply a single burst of sideways thrust while facing an object, then, without applying any additional thrust, keep turning to face the object, and you will go right around it.
Every object in the scene is assigned to one or more of 20 visibility layers.
Visibility layers have many uses:
- You can put scenery, characters, particles, and lamps in different layers, to help organize your scene.
- By changing which layers are visible, you can simplify your view of the scene and work with only one or two layers at a time.
- When rendering, only visible layers are included. You can use this to render your scene layer by layer, checking each layer separately.
- You can configure lamps to illuminate only objects in the same layer.
In Object Mode, you can tell which layers are visible by looking at the twenty small boxes located in the 3D View header between the Transform Orientation menu and the "Lock" button. The top row of boxes represents layers 1 through 10, with 1 being the leftmost and 10 being the rightmost. Similarly, the bottom row of boxes represents layers 11 through 20.
- To view just one of layers 1 - 9, press .. .
- To view just layer 10, press .
- To view just one of layers 11 - 19, press + .. +
- To view just layer 20, press + .
- To toggle the visibility of one of layers 1 - 9 without affecting the visibility of the other layers, press + .. + .
- To toggle the visibility of layer 10 without affecting the visibility of the other layers, press + .
- To toggle the visibility of one of layers 11 .. 19 without affecting the visibility of the other layers, press + + .. + + .
- To toggle the visibility of layer 20 without affecting the visibility of the other layers, press + + .
- To make all layers visible at once, press . Press again to return to your previous layer visibility setting.
The hotkeys in this section will not work if you've enabled numpad emulation in the User Preferences window. See the "User Preferences Windows" module for more details.
Holding down while selecting a layer (by keyboard or mouse) will, instead of making only that layer visible, toggle the visibility. In this way, you can select combinations or to hide particular layers.
The key to press to select all layers at once differs by keyboard layout. It is:
- (the key under Esc) on UK keyboards,
- German, Swedish, Finnish and Hungarian,
- Swiss German,
- Brazilian Portuguese,
- Italian, and
After pressing the aforementioned key, holding downwhile pressing it again will restore the visibility settings you had before you made all layers visible.
When only one layer is selected, new objects are automatically assigned to that layer. When two or more layers are visible, new objects are assigned to the most recently visible layer.
Count Your Polys
If you want to count the polygons in your scene, the data is available in the Info Header.
As you can see in the above image, this scene has 507 vertices and 500 faces (polygons).
|Applicable Blender version: 2.70.|
In this module, you will learn some basics about operating in Object mode. This is normally the default mode Blender is in when you open a new document. It is the mode where you operate on whole objects, rather than on their parts.
Many of the conventions involving selection and manipulation of objects or parts of objects apply to other modes as well, so this is a good place to become familiar with those conventions.
Open a new document, then confirm you are in Object mode by checking the mode menu.
Select the default cube by clicking on it with. You will see it framed in an orange outline.
When you select an object, you will notice a round dot appears, normally in the middle of the object, the same orange-yellow as the rest of the selection.
This is the object’s origin. It is the reference point for the object’s local coordinate system. Certain kinds of edits to the object can cause this origin to end up at a position well outside the object. If that happens, operations like transformations applied with reference to the origin may not behave as expected. However, Blender has capabilities to deal with this. They will be explained when you need them.
You can select more than one object at a time. With the cube still selected, change your view until you can see both the cube and the default lamp. Select the lamp by clicking on it with+ ( + for versions after 2.8), so both the lamp and the cube are selected. You will notice that the lamp takes on the orange-yellow colour, but the cube now has a more reddish highlight.
The active object is the last one selected. Other objects can be part of the selection, but the reddish-orange highlight indicates that they are not active. The Properties window shows properties for the active object, not the entire selection, although operations in the 3D view like moving and deleting objects will affect the entire selection. Some operations (like parenting, which you will learn about later) set up a special relationship between the active object and the rest of the selection, so for these, the order of selection of objects becomes important.
You can remove the active object from the selection with+ ; the small spot indicating the origin of the object’s geometry stays highlighted in the yellow-orange colour, even though the rest of the object loses the selection highlight. If you do this to an inactive object, it will make that object active.
Pressing+ inverts the selection. i.e. it deselects what was previously selected, and selects everything else instead. It does not change the active object.
Selecting Obscured Objects
If multiple objects lie under the mouse, you can choose which one to select by clicking+ : this will bring up a menu listing the names of the selectable objects.
Alternatively, you can add an object to the current selection, or remove it from the current selection, by clicking+ + and selecting it from the menu.
On Ubuntu 16.04 LTS, it appears that+ has the same effect as on a Window's title bar. But + + does the trick of Selecting Obscured Objects.
Selecting Everything and Nothing
Pressingdoes one of two things: if anything is selected, it clears the selection (i.e. selected objects are no longer selected). But if nothing is selected, then it selects everything. You will often see instructions to press either once or twice, to ensure that either nothing is selected, or everything is selected.
When working on a complex model or scene, things are likely to get cluttered, making it hard to see the specific part you’re working on. It is possible to hide objects, so they no longer appear in the 3D view. Select the object(s) you wish to hide, and press. This is purely a convenience for working in the 3D view, i.e. hidden objects remain unchanged when you render them.
Pressing+ hides everything except the current selection. This is a quick way to remove the clutter and narrow the view to the objects of interest.
Pressing+ brings back all hidden objects and selects them. If you lose track of what is hidden and what is visible, press this to bring everything back.
Local Versus Global View
Local view is another way of selectively hiding parts of the scene. Pressing ( for emulated numpad) hides everything that is not selected, and automatically zooms in or out as necessary so the selected objects fill the 3D view. Pressing again, restores the items to the normal global view.
This differs from simple hiding within that a render done in local view only shows the objects currently visible in that view. In particular, if your lights are excluded from the local view, you are liable to see black blobs in place of your objects.
How do I determine the viewing mode? Look at the words in the upper-left corner of the 3D view. They indicate your current view orientation and perspective settings (e.g. “User Persp”). If the word “(Local)” appears at the end of the string, you are in local view. Otherwise, you are in global view.
Border Select (Box Selection)
A quick way to select many objects at once is with the Border Select (box selection). Press to activate it. You will see a pair of dotted crosshairs appear centred at the current mouse position. Drag diagonally with to mark a selection rectangle, then release the . Everything within the rectangle will be added to the selection. If you didn’t mean to engage box-selection mode, pressing exits border select mode.
Alternatively, to remove things from the current selection, after pressing, drag the selection rectangle with . When you release the mouse button, everything in the drawn box will be deselected.
Circle Select (Brush Selection)
Another way to select several objects at once is with the Circle Select (brush selection), engaged by pressing . In this mode, clicking or dragging on objects with adds them to the selection, while removes them from the selection. Thus the mouse becomes a brush that you can use to “paint” objects in or out of the selection.
The circle showing the size of the brush can be adjusted with the mouse wheel. This allows you to use a broad brush for selection of lots of objects at once, or a finer one for better control.
Clickingor pressing terminates Circle Select mode.
The manipulator appears in the middle of the selection. There are three kinds of manipulator as shown in the illustrations. It can be used to apply translation (position changes), rotation and scaling (size changes) to objects. Its appearance changes according to which of these functions are enabled. You can click on the menu transformation buttons that appear when the manipulator is visible, to choose a single transformation, or shift-click to enable more than one simultaneously. You can toggle the visibility of the manipulator with+ , or by clicking the menu button with the red, green and blue arrows.
If you have troubles selecting the red arcs of the rotation manipulator select File→ User Preferences... System → Selection and change it to "OpenGL Select" or "OpenGL Occlusion Queries".
Transform orientations: the “Orientation” menu governs how the axes of the manipulator are aligned, with the default “Global” corresponding to the global coordinate system. Other useful options are “Local”, which corresponds to the local coordinates system of each object, and “View”, which is always aligned to your view.
To demonstrate this, click on the camera withso that it is the only object selected. Set the manipulator to do only translations (blue arrow button is selected in menu), and ensure the orientation is set to “Global”. Drag any of the manipulator's coloured arrows with to move the camera in the corresponding direction.
Now switch the orientation to “Local”. You will see the manipulator arrows re-orient themselves. Note that the Z-direction (blue arrow) is now in the direction of the camera view. The local co-ordinates of the camera have the optical axis of the camera running along the Z axis. By default, that is pointing towards the cube object.
The cube, by default, has its own local Z-direction running vertically.
With the manipulator orientation still set to Local, add the cube to the selection with+ . You will see the manipulator move so it is in the centre of the selected objects. It is now between the camera and the cube. Now if you drag the manipulator Z axis arrow with , each object will move along its own version of that axis. The camera moves towards or away from the cube and the cube rises or falls.
Switch the orientation to “Global”, and try dragging a manipulator arrow again. This time, both objects will appear locked together and will move in the same direction, along the same (global) axis.
The manipulator is not the only way to apply transformations to objects. That can also be done via keyboard shortcuts.
Hide the manipulator to reduce clutter. Select the cube, and only the cube, with. Now press to Grab the object. The selection outline around the object turns white, as it did when you were dragging with the manipulator, except this time, you didn’t press any mouse buttons. Now move the mouse without pressing any buttons, and you will see the object move along with it. Press or to terminate the movement and leave the selected object at the new position, or or to cancel the operation and leave the object at its original location.
Similarly, useto Rotate the object, and to Scale it.
You can constrain the movement to particular axes by pressing the appropriate axis key. For example, pressto start moving the cube again, then press and you will see a bright colored line appear parallel to the global X-axis. Now when you move the mouse, the cube will move along only that colored line. Similarly and constrain movement to the Y and Z axes respectively. The colored lines that appear are a brighter reddish, green or blue that correspond to the red, green or blue lines for the X, Y or Z axes, respectively.
Transform orientations: to constrain the transformation to a different set of axes, press the constraint key twice. The coordinate system used depends on the selection in the Transform Orientation menu:
- Local or Global — the transformation happens in the object’s local coordinate system.
- View — the transformation is aligned to view coordinates.
For example, with the default “Global” selection from this menu, select the camera with, press to move it, then press twice, and you will see the coloured line orient itself along the direction of view of the camera.
The axis constraints also work with scaling, and rotation (which only happens around the specified axis).
You can also constrain movement and scaling to happen along two axes, but not the third one, by holding downwhen typing the axis constraint. For example, followed by + will constrain movement to the global X-Y plane (i.e. any direction except along the Z-axis). To constrain movement to the local X-Y plane, type the contraint twice: + + .
Here’s a summary of what the transformation hotkeys do, with and without constraints:
|Key||without constraint||followed by axis||followed by-axis|
|moves in plane perpendicular to view direction||moves along axis||moves in plane perpendicular to axis|
|rotates about view direction||rotates about axis|
|scales uniformly along all axes||scales along axis||scales uniformly in plane perpendicular to axis|
In addition, the hotkey sequenceenables free rotate, i.e. the object can rotate around all three axes as you move the mouse.
Transforming by Numbers
Sometimes you need to position things accurately, using calculated numbers, instead of estimating by eye. Blender can do that too. Simply type the number after the transformation hotkeys before pressingto confirm the operation. For example, will move the selection by 1 unit in the positive X direction. will move by 1 unit along negative X. Decimal points are allowed, thus will scale the selection by a factor of 0.5, or 50%.
Rotation works similarly, using degrees clockwise around the selected X, Y or Z axis.
Yet another way is shown at right, in the Transform panel that appears at the top of the Properties shelf (pressto toggle its visibility at the right side of the 3D view). Here you can see the existing transformations values. You can drag the sliders to change them, or click on them and enter new values.
Choosing the Pivot Point
When you do a scaling or rotation operation, you can choose the pivot point, which is the central origin point that remains unaffected by the operation. By default this is the “Median Point”, or centre point of the selection, but the Pivot Point menu lets you choose some other options. For example, select both the cube and the camera, and rotate them ( ). By default they will rotate around their common centre. Now go to the Pivot Point menu and choose “Individual Origins” and rotate your two selected objects with again, and you will see each one now rotates about its own centre, rather than the common one.
Another useful pivot option is “3D Cursor”, which places the transformation origin at the 3D cursor location.
Finally, the button with three dots and a double-headed arrow immediately to the right of the one that pops up the Pivot Point menu is titled “Manipulate center points.” Selecting this means transformations do not rotate the actual objects themselves, only their positions. To see the effect, you need to choose a pivot point that is not the object’s origin. Now try rotating the object. You will see its centre describes an arc around the pivot point, without changing the object's orientation. Think how the seats in a Ferris Wheel rotate around the wheel's pivot, yet still maintain their orientation.
Similarly scaling will change the distance between the chosen pivot point and the object’s origin, but will not affect the size of the object itself. A bursting firework scales rapidly in this way.
Why can’t I rotate or scale objects? One pitfall you might encounter is that you select an object, try rotating withor scaling with , and nothing happens, though moving with still works. It’s quite likely you have the “Manipulate center points” button active when you didn’t mean to. Check if it’s active, and click it to deactivate if so.
Hotkeys — there are keyboard shortcuts for all the above options:
|Bounding Box Center|
|Toggle Manipulate Center Points||+|
Basic Camera Technique
The camera viewis very useful for making adjustments to your camera while getting continuous feedback on how the render will look. This view shows a framing rectangle covering the area that will appear in the render, surrounded by a passepartout which gives a darkened view of the surrounding part of the scene. You can use the mouse wheel to zoom in and out, adjusting how much of your view is the rendered area and how much is passepartout.
In this view, useon the framing rectangle to select the camera, and it will show the usual orange-yellow highlight. The manipulator will not appear even if enabled, so you must use the transformation hotkeys to perform camera transformations.
Useto move the camera around parallel to the view plane. Since the view stays locked to the camera, you will see the scene move in the direction opposite of what you might expect.
The camera’s local Z-axis lies along its direction of view. This allows useful operations liketo move the camera in or out without affecting the direction in which it’s pointing. Also the X axis runs left to right in the camera view so rotating around X will adjust the up-and-down pitch angle. Rotating around the vertical Y axis will change the yaw (left-right) angle, and you can rotate around the optical axis of the camera using to produce an effect of rolling the view around the visual axis.
Another useful technique is to position the 3D cursor at a point of interest, set the pivot point to the 3D cursor, then rotate the camera about a global axis, like the global Z-axis (), to adjust the angle of view while keeping the same objects in view, and without altering the distance of the camera from the point of interest. In real life you'd get that effect by walking in a circle around your subject with your camera mounted on a Steadicam rig.
Scaling the camera object changes its size as shown in the 3D view, but has no effect on the actual render. Regardless of what axis constraints you try to apply, the camera object will always scale uniformly along all axes.
You can also use Fly mode+ in camera-view mode to fly around the scene, taking the camera with you.
Another choice for moving your camera in Camera View is to bring up the Properties panel () and, in the View section, tick the box next to Lock Camera to View. Now you will be able to use the to "move objects" just as you move things around in other views such as the 3D view. Holding down the and dragging will rotate, + will allow you to "move the object" around in the view (panning), and the scroll wheel will allow you to "move the object" closer or farther from the camera. You are actually moving the camera with these manipulations and not the object(s) themselves.
Adding/Removing Objects, Undo/Redo, Repeat
Select the cube withagain. Press either or and, after confirming the popup, the cube disappears! It has been deleted from your scene. Unlike mere hiding, it really has disappeared. Press + to undo your last operation, and it reappears.
Click withto position the 3D cursor away from the default cube. Press + to bring up the Add menu, go to its Mesh submenu, and add another cube to the scene. Again, undo with + , and you are back to a single cube again.
Now press+ + : this will undo the undo, and redo the last operation you undid, bringing back the second cube.
Try adding a third cube. Now+ should undo that and take you back to two cubes, and pressing + again should undo the addition of the second cube, taking you back to one. Try + + at this point to restore the second cube, then + + again to restore the third one.
Blender remembers up to the last 32 things you did (depending on the limit set in your user preferences) in its undo stack. You can go backward and forward through it with+ and + + .
Sometimes you want to perform an action repeatedly. To repeat the last action, type+ .
Earlier, you learned about showing and hiding layers in the 3D view. To assign layers for selected objects, press. The same keyboard shortcuts apply here as when choosing which layers to display, i.e. for only the first layer, for only the second etc, + to include/exclude the first layer and so on.
After assigning an object to a different layer, it disappears! If this happens to you, it’s because the layer(s) you assigned to the object, and the layer(s) you currently have visible in the 3D view, have nothing in common. Simply change the visible layers to include at least one of those you assigned the object to, and it will reappear. For example, if currently only layer 1 is visible, and you assign an object to only layer 2, it will disappear, but reappear when you change the visible layer to layer 2.
Object, Action, Settings
Bring up the Add menu again (+ ). This time, add a new cylinder mesh to the scene. Look to the left of the 3D view, in the Tool Shelf (toggle its visibility with if it’s not visible), at the bottom you should see a new panel has appeared, titled “Add Cylinder”. Near the top of it is the “Vertices” number, initially defaulting to 32, which gives a fairly round-looking cylinder. Reduce it to 6, and adjust the view as necessary to get a good view of your “cylinder”, and you will see it is now a hexagonal prism. Change the number of vertices to 3, and it becomes a triangular prism.
This is an example of an important user-interface convention that runs right through Blender: first you select the object you want to perform an operation on as appropriate (not applicable here because we are creating a new object), then you perform the specified action with some default settings, and finally you adjust the settings to give the exact result you want. This way, instead of getting a popup before the action is performed, into which you have to put the right settings and hope they will give the right result, you get to interactively adjust the settings and immediately see the results, without having to continually redo the operation and deal with popups.
Meshes and Edit Mode
|Applicable Blender version: 2.67.|
A mesh is one of the most important and frequently-used object types in Blender. While there are other types of objects that can be used to model parts of a model or scene (text, NURBS patches, etc.), they often get converted to meshes at some point anyway, because it is the object type that offers the greatest amount of detailed control. And as it happens, Blender offers more functions, both built-in and available as addons, for dealing with meshes than for any other object type.
Edit mode is the mode in which you make changes to the internals of the active object. Not every object has an Edit mode (e.g. cameras), and the details of what you can do in Edit mode vary between the object types where it is available. This module specifically covers Edit mode for mesh objects.
What Is a Mesh?
A mesh is made up of one or more vertices; each vertex is just a point in space. A pair of vertices can be joined by a straight line called an edge, and a complete loop of edges can be filled in to form a face.
It is the faces that make up the visible surface of the object. The edges and vertices are essentially geometrical "scaffolding" necessary to hold the object together.
A face must have three or more sides (edges). Prior to version 2.63, only three or four sides were allowed, so faces had to be triangles or quadrilaterals (usually abbreviated to quads) respectively. Starting with v2.63, and the introduction of the BMesh architecture, that restriction has been lifted. You can have faces with 5 or more sides, but you will usually find that things work best if all faces, as far as possible, are quads. Particularly when constructing a model for animation purposes.
Blender’s Object-mode “Add” menu (+ ) contains a Mesh submenu with a collection of pre-made mesh objects. Think of these as starting points. They make building your own objects easier by enabling you to modify an object that is an approximation of the form you want instead of having to construct a mesh entirely from scratch.
Introduction to Edit Mode
Start a new model. Hide the manipulator if it is visible (+ ). You should be in Object mode. Click with on the default cube to ensure it is selected and the active object.
You can switch modes using the mode menu, as you previously learned. However, because switching between Object mode and Edit mode is such a frequent operation, it has a keyboard shortcut:. Do this now, and you should see the appearance of the cube change, as shown at right. The mode menu should also update. Press again, and you should be back in Object mode. Press once more before continuing, to ensure you are in Edit mode.
Note the following features of the cube, and how they relate to the description of a mesh above:
- The dots at the corners are the vertices.
- The lines joining them are the edges.
- The filled areas bordered by the lines are the faces.
In Edit mode, the header (it's at the bottom) of the 3D View window changes to show the selection-mode controls. If you hover over each of the buttons in the group of three, you will see they represent vertex-select, edge-select and face-select respectively. You can shift-click to enable more than one at a time.
In vertex-select mode, you select a single vertex by clicking on it with, and select more than one by shift-clicking on additional vertices with . Shift-clicking with on an already-selected vertex will deselect it.
Pressingwill select all vertices if none are currently selected, otherwise it will unselect all vertices.
Edge-select mode works in a similar way, except with edges instead of vertices. Similarly, face-select mode will allow you to select and unselect faces.
The single button immediately to the right of these three is titled “limit selection to visible”. When it is active (the default), the mesh object being edited is displayed as opaque which means that vertices, edges or faces on the side away from you are hidden and cannot be selected. Click this button, and the object becomes translucent, allowing clicking through front faces to select parts of the mesh behind them.
Another useful display mode for working in the 3D view is wireframe, which can be selected from the Viewport Shading menu or toggled with the key. In this mode, the faces become transparent, almost invisible, and the edges and vertices are displayed more prominently.
Here is what these various selection and display modes look like in combination: in the first row, a single vertex is selected. In the second row, a single edge, and in the third row, a single face. In the first column, limit-selection-to-visible is enabled. In the second column, it is disabled, and in the third column, wireframe mode is enabled.
Selection Mode Hotkeys
You can also switch selection modes with+ . In the menu that appears, you can switch to a single selection mode by selecting it with the mouse or up/down-arrow keys and pressing or . But if you press + or + that toggles the enabling of only that selection mode, without affecting the state of the others, as does shift-clicking on the icons above.
In common with other Blender popup menus, you can quickly select an item from the+ menu and immediately confirm by pressing one of , or to select the first (vertex), second (edge) or third (face) item in the menu. Or, + , + and + while the menu is up, will toggle the enabling of vertex, edge, and face-select modes respectively.
You can use+ to select multiple items, and + to invert the selection, just like in Object mode. Only here, the “items” are vertices, edges or faces, depending on the selection mode in effect. The active (last-selected) part is shown in white, while the rest of the selection (if any) is drawn in the usual orange-yellow colour.
As mentioned above,works similar to the way it works in Object mode, only instead of applying to everything, it applies to all parts of the object being edited.
, + and + work in a way analogous to their behaviour in Object mode. Again, instead of applying to everything, they apply to all parts of the object being edited.
Remembering What’s Hidden: If you switch out of Edit mode with some parts hidden, they will reappear, then disappear again when you re-enter Edit mode, i.e. each object remembers what was hidden when you last edited it.
Local Versus Global View
You can toggle local/global view in Edit mode, as you can in Object mode. However, instead of narrowing the view to one or more selected objects, it narrows it to just the object being edited.
Border Select (Box Selection) & Circle Select (Brush Selection)
and work analogously to the way they do in Object mode, i.e. you select multiple items by drawing a box or by “painting” over them.
Select More, Select Less
Edit mode has some additional selection capabilities. To demonstrate them, let’s use something other than the default cube, for a change.back to Object mode, and delete the cube. Now add ( + ) a Grid object. into Edit mode, and you will see that the grid is made up of 9×9 faces, or 10×10 vertices. Initially they will all be selected. Use to unselect them then to brush-select a few vertices in the middle. End brush-select mode with or . Now watch what happens to the selection when you press + (select more). Additional vertices adjacent to those already selected are added to the selection. Now try + (select less), and you will see the vertices on the edge of the selection are removed from it.
Manipulator, Transformation Hotkeys, Pivot Point
All of these are available for use in Edit mode as they are in Object mode, except for the “Manipulate center points” button.
Note that scaling vertices scales the distances between them. The vertices themselves have no size, so they do not get larger or smaller. Similarly, rotating vertices only changes their direction relative to the pivot point, since a featureless point itself has no orientation.
The Global, Local and View options in the Transform Orientation menu apply in Mesh Edit mode as they do in Object mode. In addition there is Normal mode, where the transformation axes are aligned relative to the selection:
- If a single face is selected, the X and Y axes are aligned along the face, while the Z axis is aligned perpendicular (normal) to the face.
- If a single edge is selected, the Z axis is aligned along the edge, with the X and Y axes perpendicular to it.
Other selections are also possible. Feel free to investigate their behaviour for yourself.
Thus, with a single face selected,will move the face along its normal.
In addition, it is possible to define the current Normal transformation orientation as a custom orientation for use in transforming other vertices and even other objects. To do this, you need to go to the Properties Shelf, which is made visible on the right of the 3D view with. Near the bottom is the Transform Orientations panel which contains a Transform Orientation menu which looks the same as the one in the header of the 3D View window, except it also has a “+” button next to it. Click the "+" and the current Normal transformation orientation will be added to the menu initially labeled “Vertex”, “Edge” or “Face”, depending on what is currently selected (and with a unique numeric suffix added if there is already a custom orientation defined with that name). Now if you look in either Transform Orientation menu, you will see a new selectable item, in a separate section above the five standard items.
With your new orientation option selected, an editable text field will appear in the Transform Orientations panel, allowing you to change the name if you wish, and there is also a “X” button allowing you to delete the orientation item when you no longer need it.
With your new orientation option selected, you can now select a different part of the object, or eveninto Object mode and select some other object. The manipulator and the doubled axis hotkeys will now align their transformations along this custom orientation. This is handy, for example, for aligning objects to a sloping plane.
When trying to produce natural, organic shapes, moving vertices one by one gets tedious. To produce smoother looking shapes, you need a mode where unselected vertices close to the selection also get some movement. In contrast to the sharp distinction between selected vertices which are moved and unselected ones that remain in place, there is a gradual transition from one to the other.
This is where proportional editing comes in. If you select “Mesh” in the header and examine the pop-up menu, you will see two submenus, titled “Proportional Editing” and “Proportional Editing Falloff”. The former toggles the mode on and off, the latter controls the falloff function choice. There is also an icon for “Proportional Editing” in the header of the default 3D view. Look to the right of the "Limit Selection to Visible" (on edit mode). The hot key is the letter O. Pressing will toggle between Enable and Disable. Pressing + will change the Falloff type.
The “Proportional Editing” submenu has 4 options: “Disable”, “Enable”, “Projected (2D)”, and “Connected”. Do you still have the Grid object you created in the “Select More, Select Less” section above? If not, add a fresh Grid object. Switch to Edit mode, and ensure that just a few vertices in the middle are selected. Enable proportional editing, and now useto move the selected vertices. You should notice 2 things:
- unselected vertices near the selected ones also move, and
- there is a white circle enclosing all the vertices that undergo any movement.
Try using the mouse wheel while moving the vertices, and you will see the white circle grow or shrink, and the proportional region of influence will grow or shrink correspondingly.
Try different falloff functions in the “Proportional Editing Falloff” submenu. Some ensure the mesh stays smooth and curvy, others give a more angular effect, etc.
The third option to "Disable" and "Enable" proportional editing is "Projected (2D)". This view is similar to enabled, except depth is ignored. The radius of the influence region is applied to the mesh two dimensionally.
The fourth option to “Disable” and “Enable” proportional editing is “Connected”. This one makes a difference in more complicated meshes, which might have folds or concavities in them. In this situation, “Enable” affects all vertices within a particular distance of the selected ones, while “Connected” only measures the distance via connected edges, rather than directly through space. This lets you move one part of the mesh without affecting another part which might be located nearby purely as a result of a fold.
Of course, proportional editing works with scaleand rotate operations as well.
Now let’s try deleting parts of a mesh. This is the menu that comes up when you pressor when editing a mesh. For now, we will concentrate on the first three items.
First, go into face-select mode. Select one face of the default cube, press the delete key, and select “Faces”. As shown in the screenshots, the selected face should disappear.
Use+ to undo your previous deletion. Now go into edge-select mode. Select one edge this time. Press delete again, this time select “Edges”. As the screenshots show, the selected edge disappears, but the faces bordering that edge also disappear. Faces cannot exist without their bordering edges!
Use+ to undo your previous deletion again. Go into vertex-select mode. Select one vertex, make sure it’s the one closest to you so you get the best view of the effect. Press delete, and select “Vertices”. Not only does the selected vertex disappear, but also the edges connected to that vertex. Edges cannot exist without their endpoint vertices. And since those edges disappeared, the faces dependent on them for their borders were deleted as well.
So, to recap:
You can undo your last Edit-mode operation with+ , and undo your undo with + + , similarly to Object mode. However, Edit mode maintains its own undo stack, separate from the Object-mode stack. To undo/redo an Edit-mode operation, you must be in Edit mode, not Object mode.
Back to the default cube and Edit mode. Ensure you are in vertex-select mode with nothing selected. Do a+ somewhere near the cube. Do you see a little orange-yellow dot appear where you clicked? You just added a new, unconnected vertex to the mesh. (If not, you may need to set this hotkey in user preferences - + + and search for "duplicate or extrude".)
Undo your addition (+ ). Select an existing vertex with . Now + to add a new vertex again. You will notice that it is connected to the previously selected vertex by a newly added edge as well. Since the newly added vertex is now the selected vertex, doing + again at another position, and so on repeatedly, lets you construct a whole chain of new edges. But what good are edges and vertices without faces?
To construct a face, you need a closed loop of edges. To close a loop of edges, select all the vertices in the chain, and press. That will add another edge joining the first and last vertex into a complete loop of edges and fill in the loop with a new face.
If you want to close the loop without filling in the face, select only the first and last vertex in the chain before pressing. Since only two vertices are selected, a new face will not be added, i.e. it will only add an edge joining the two vertices.
You can also extrude new sections of mesh with a single click in this way. Try selecting two adjacent corner vertices of the cube (i.e. two joined by an edge). Now+ near them, and you will see you’ve created two more vertices, joined to the previous two by a new face. + again, and you can construct a whole sheet of new mesh in this way.
Undo all your additions, and get back to the pristine cube. Now select all four vertices of a single face.+ near your selection, and you should have four new vertices (corresponding to the original four you selected), plus a new face connecting them, plus four new faces connecting them to the original four. (You may not have noticed it, but the face formed from the original four vertices has been removed as well.) Another + does the same thing again. So with just a few clicks, you started with a cube and ended up with something (see at right) that is starting to resemble — who knows? A square-cross-sectioned piece of some wonky-looking pipe, perhaps?
It is possible to remove vertices without leaving holes behind in the mesh, by merging two or more vertices into one. Select the vertices you want to merge, and press + ; a menu will pop up with some options, including whether to position the resulting vertex in the middle of the ones being merged, or at the position of the first or last one you selected. The resulting vertex inherits all the edges that were connected to the vertices being merged, as well as the faces connected between those edges.
Sometimes an operation creates duplicate vertices in exactly the same positions, or very close together. You can merge these en masse by ensuring you have selected all possible candidate vertices (e.g. the whole mesh), bringing up the Vertex Specials menu () and selecting the “Remove Doubles” item. Look for a message saying “Removed n vertices” to show briefly in the Info window. If n is 0, nothing was done. If you look in the lower left part of the Tool shelf, you will see a “Remove Doubles” panel has appeared, with a “Merge Distance” slider that governs the maximum distance allowed between vertices that are merged. Change this value as appropriate (either by clicking on the left and right arrows, or by clicking and typing in a new value and pressing ), and the Remove Doubles operation is immediately redone. A new message will indicate how many vertices were removed. Simply keep adjusting the value until you are satisfied you haven’t removed too many or too few vertices.
Normals and Shading
|Applicable Blender version: 2.63.|
Open a new Blender document. Delete the default cube, and add a “UV Sphere” mesh. In the “Add UV Sphere” panel which appears at the lower left of the Toolshelf (pressto make the Toolshelf visible if it’s not), set both the Segments and Rings to a low number, e.g. 8. The result will be very angular, as shown to the right, not round like you would expect a sphere to be.
As you can see, the surfaces of the object look a lot smoother and curved, even though the outline or silhouette is just as angular as before.
Those spiky little lines are the normals; the green ones in the middle of each face are face normals, the blue ones protruding from each vertex are vertex normals.
In the physical theory of light, the normal is a line perpendicular to the surface of the object the light is hitting. When your eye (or the camera) C is positioned on a plane through the normal of a particular surface observing a certain surface point P illuminated by a coplanar light source L, a specific amount of light will be reflected and hence be registered by the camera depending on the physical characteristics of the surface. The observed intensity of reflected light is at a maximum if the angle C-P-L is divided into two equal halves by the normal.
In the real world, a lot of surfaces are curved or otherwise not flat. But a mesh can only be made up of straight edges and flat faces. So how can it represent an object with a curved surface?
When you added the UV sphere to your scene, you had the option of specifying how many segments and rings it was made from. The more of those present, the closer the geometry approximates a curve. However, the more there are, the longer the render will take, and the more memory the model will consume to hold information about all the extra vertices, edges and faces.
Which is where that “Smooth” shading button you clicked comes in. It applies a trick called Phong shading. Instead of doing the lighting calculation based on a normal for each face as the physical theory says you should, it starts with a normal assigned to each vertex, and interpolates the normal at each point on a face from the vertex normals at its corners, based on the distance at that point to those corners. The result fools the eye into seeing curved, rounded surfaces where there aren’t any.
This completely violates the laws of physics. To start with, how can you define a “normal” which is perpendicular to a point? But as you can see, the results look rather good, with relatively little extra computation involved, much less than actually generating all the extra geometry.
As you learn more about computer graphics, you will come across more tricks like this. Physically accurate modelling is still very difficult to do, even with modern computers, and the results may not look all that good. But by adopting a bit of lateral thinking that goes completely against physics, we can often, ironically, come up with much more realistic-looking results.
Not So Smooth?
If you have been adding lots of vertices, edges and faces to your mesh, you may end up with discontinuities in smooth shading causing unsightly blotches, as shown to the right.
Assuming your mesh is constructed properly (e.g. no edges and faces cross each other in physically impossible ways), the most likely reason for this is the normals in the newly added vertices and faces are pointing the wrong way. To fix it, select the troublesome part of the mesh (or select the whole thing) in Edit mode, and press+ to recalculate all the normals. Re-render the scene to confirm the shading discontinuity has disappeared.
Note the different meaning of+ in Edit mode. In all other modes, it opens a new default Blender document!
More Mesh Editing Techniques
|Applicable Blender version: 2.67.|
You previously scratched the surface of the tools that Blender provides for editing meshes. This page will introduce more of them.
Adding More Mesh Pieces
Start with the default cube again. Select it andinto Edit mode. Press + to bring up the Add menu. Instead of all the submenus with all the objects you could add in Object mode, you will see only a single menu containing only mesh objects. Select another cube, and use to move it away from the first cube.
If youinto Object mode, you will see that the two cubes look like separate, disconnected objects, but they are in fact one object, and cannot be selected separately in Object mode. You can back into Edit mode, and make connections between the vertices of the two cubes, which you cannot do with separate objects. Therefore:
A single mesh object can be made of separate, disconnected pieces.
If you have some part of a mesh selected, pressing+ will select all other parts of the mesh that are connected to the already-selected parts. In the above case of the object made up of two disconnected cubes, you can on a single vertex of one cube, then use + to select all the rest of that cube but not the other.
Another way to do linked selections is to simply move the mouse over some part of the piece you want to select, and pressto immediately select everything connected to that. Conversely, + will unselect everything connected to the vertex under the mouse.
Separating and Joining Meshes
You can separate a part of a mesh into its own object. The part you are separating doesn’t have to be disconnected from the rest of the mesh. Simply select the part you want to separate in Edit mode, and press, and in the menu that appears, choose “Selection”. You will see the selected part immediately change to a reddish-orange highlight, indicating it is part of the object selection but not the active object.
Conversely, you can join two or more mesh objects into one. Select all the desired objects in Object mode, and press+ , and you will see them all immediately take on the orange-yellow highlight indicating they are all the active object. into Edit mode, and you can confirm all are editable as part of the same mesh object.
You previously discovered how to add whole new sections to a mesh with Extrude function, which lets you do this with a bit more control.+ . Blender also has a proper
Start with the default cube, as usual. Go into Edit mode. Select just the top four vertices. Pressto start extruding, and move the mouse roughly along the direction of the Z-axis. You will find yourself dragging out a whole new face formed from four new vertices connected to the ones you previously selected. You will notice also that the movement of the newly-added part of the mesh is automatically constrained to be parallel to the Z-axis. Press or to finish the extrusion operation.
Deselect everything. Now try selecting another four vertices of the original cube, say making up a face pointing along the X-axis. Now if you extrude these, you will see that the extrusion is automatically constrained to move only parallel to the X-axis.
A quirk of the extrusion function is that if you pressand then immediately abort with or , the additional mesh piece is still created, but it is left in the same position as the original mesh. To really abort the extrusion, you have to undo it with + .
More Extrusion Options
+ brings up the Extrude menu, which gives you access to more options, depending on what you have selected:
- “Region”—extrude the entire selected area as one, exactly equivalent to .
- “Individual Faces”—if you have more than one face selected, then they are extruded separately. In particular, any edge common to two selected faces will give rise to two separate extruded edges, rather than one.
- “Edges Only”—extrudes only the edges; new faces are created only connecting the new edges to the existing ones, not between the new edges.
- “Vertices Only”—extrudes only the vertices; edges are created only connecting the new vertices to the existing ones, not between the new vertices, and no new faces are created.
Edge Loop Selection
Edge loops are an important concept when constructing meshes. They are so important that Blender provides a shortcut for selecting an entire edge loop with one click: + on an edge or vertex that is part of the loop you want to select, and it will select the entire loop. Alternatively, + + adds an edge loop to the selection; or, if the part you click on is already selected, it will deselect the entire loop.
For example, try experimenting with a UV sphere: every line of “latitude” and “longitude” in this mesh is an edge loop.
Sometimes you need to add more vertices to the interior part of a mesh, perhaps to flesh in some detail. The loop cut function lets you add more edge loops between existing ones.
Ensure you are in Edit mode. It doesn’t matter what parts of the mesh are currently selected. Press Loop Cut function. You will see a magenta-coloured loop wrap itself around different parts of the mesh as you move the mouse. You can press or to abandon the operation at this point, or once you see the loop appearing around the correct part of the mesh, you can use or to proceed. Now the magenta colour changes to the usual orange-yellow selection highlight, and will now restrict itself to sliding along this section of the mesh as you move the mouse. If you press or at this point, you will end up with a new loop of vertices and edges at the last-shown point, while or will still create the new loop, but leave it positioned at the midpoint.+ to activate the
When the loop is still at the magenta stage, you can use the mouse wheel to increase the number of cuts to 2 or more. You can also type a number of cuts using... .
Edge Loop Deletion
Conversely, you can get rid of edge loops as well, reducing the complexity of the surface without leaving holes in it. Select the edge loop (the quick way is+ on a component edge or vertex as described above), then bring up the deletion menu ( or ) and select “Edge Loop”. The selected loop will disappear, and adjacent edges and faces will be merged.
A loop cut always cuts a complete loop. Alternatively, you can subdivide just a selected part of the mesh: make your selection, then press to bring up the Vertex Specials menu, and select the top option, “Subdivide”. This will create one cut, but a panel will appear at the lower left of the Toolshelf ( to make it visible at the left of the 3D view if it’s not), where you can alter the number of cuts and other settings. This same option is also available on Edge Specials + .
Another option is the second one on the Catmull-Clark interpolation to give more of a curve rather than a flat subdivision.menu: “Subdivide Smooth”. This one computes a
Subdivision Surface Modifier
A modifier causes some change to the geometry of an object just before it gets rendered. The change does not affect the object as you view and edit it in the 3D view, or as it is stored in the document (unless you apply the modifier, which makes the change permanent). This allows you to create some complicated effects at render time, while the original mesh stays simple and easy to edit. Modifiers for the active object are applied and controlled in the Modifiers tab in the Properties window.
A subdivision surface modifier (also known as a “subsurf” modifier) applies the Catmull-Clark interpolation discussed above as a modifier. Being a modifier, it applies to the entire object, not just to selected vertices. But since the original mesh is preserved, you use it as a control cage to adjust the shape of the interpolated curve.
Start with the default cube selected in Object mode, as usual. Go to the Modifiers tab in Properties . When you select “Subdivision Surface” from the “Add Modifier” menu, a new panel appears as at right. Notice the two value sliders under the “Subdivisions” heading; 'View' controls the level of subdivision within the 3D view, while 'Render' applies to the actual render; the higher the number of levels, the closer to a curve the interpolated geometry becomes. Having two separate settings for working environment and render allows for faster operation in the 3D view, with the usual tradeoff of lower quality, while still allowing maximum quality for the final render.
Keyboard shortcuts: Because the Subdivision Surface modifier is so heavily used, there is a set of hotkeys for adding the modifier to the current object if it doesn’t already have one, and setting the number of subdivision levels in the 3D view:+ .. + for setting the view levels to 1 .. 5 respectively.
As soon as you add the modifier, the appearance of the cube should change to look something like at right (here shown with just one level of subdivision).
The upper part of the panel (from the “Apply” and “Copy” buttons upwards) is common to all modifiers. Note the X button at the right. Clicking it gets rid of the modifier. Notice also a group of 4 icon buttons in the middle, the leftmost two look like a camera and an eye. The icons are defined as follows (from left to right):
- Use the modifier during rendering
- Show the modifier effect in the 3D view
- Show the modifier effect in the 3D view in Edit mode (if this is unchecked and the previous one is checked, the modifier effect disappears while in Edit mode)
- Show the mesh as though the modifier were applied to it in Edit mode.
Unchecking the first one lets you disable the modifier without losing its settings. The remaining three can be handy if you’re trying to disentangle the effects of different modifiers during editing.
When the third button is enabled, the mesh will look like this in Edit mode. The original mesh remains highlightable and editable. A preview of the effect of the modifier is also visible, and responds immediately to any changes made to the original mesh. (Try moving some vertices around, and see what happens.)
The fourth button goes one step further and acts as if the modifier has already been applied, while allowing you to edit only those parts corresponding to the original mesh. (This button affects the behavior of the third button. It cannot be used independently, and may disappear if the third button is unchecked.)
Sharpening the Curves
The subdivision surface modifier offers much more control over the resulting shape than might be apparent from above. For example, you may not want uniform curvature everywhere, you may want some parts of the shape to have sharper edges. This can be achieved in two ways:
- by applying a crease value to selected edges
- by strategic positioning of additional vertices in the control-cage mesh.
Applying a Crease
Select the edges where you want the curve to be sharper. Press+ . Note how the curve gets pulled more or less closer to those edges as you move the mouse. The selected edges take on a magenta colour, indicating they have a nonzero crease value applied.
The crease value can be seen and edited in the Transform panel at the top of the Properties Shelf at the side of the 3D view (you can toggle its visibility with. Values can range from 0.0 (no crease, the default) to 1.0 (maximum sharpness of the edge).
For example, start with the subdivided cube example as above. Press+ to start a loop cut, and position the magenta outline something like this:
... and move the mouse so the newly-added loop moves closer to one side of the cube. See how the subdivided mesh develops a sharper curve on this side?
To confirm the placement of the new loop, pressor .
Which to Use?
The basic principle is, the closer together the vertices are, the more control you have over the curve at that point. So the question is, do you just want a sharper edge, or do you want more detail? That will govern whether you need to add vertices, or just apply a crease to the existing edges.
|Applicable Blender version: 2.63.|
Open a new default Blender document. Without doing anything else, hitto render the default cube with the default settings. The result should look something like the image to the right.
Note the lower left visible face of the cube is completely black because the default light is at the upper right.
Check the box next to the title, and leave the “E:” (energy) value at its default 1.0. This gives us a pervasive, directionless light, illuminating all objects equally from all directions, which means there will be no shadows. Do another render, and it should now look like the image to the right.
See how we have gone from inky-black shadows to no shadows at all. In the real world, lighting is almost never perfectly uniform, and this variation of light and shade is important to help us distinguish details of the scene around us. Without such variations, everything devolves into featureless blobs.
Now undo your deletion of the default lamp (or move it back to layer 1). Enable Environment Lighting again, but this time lower the Energy value to 0.1. Do another render, and it should now look like the image to the right. The shadowed face is still shadowed, but not enough to make it impossible to see any details it may have. This is usually the type of effect you want, unless you are aiming for really dramatic contrasts.
So the lesson is:
A single light is rarely enough for a good looking scene.
As you learn more, you will find that it is common to use two or three lights, or even more, to ensure proper illumination of a scene. In simple tutorials, where no explicit details are given about lighting, you can probably get by with the default light, plus some environment lighting (as we added earlier) to soften the shadows.
|Applicable Blender version: 2.57.|
In this module, you'll learn how to extrude and merge vertices of a mesh and how to save a model. This module also introduces the File Browser window type.
Your first model will be a house, which we will develop over the course of several modules. Here we will start with four walls and a pyramidal roof. Simple! Since you're going to use the default cube as a base, all you actually need to build is the roof!
Editing in Blender generally involves four steps:
- Selecting an object to edit.
- Activating Edit Mode on that object.
- Selecting part(s) of the object to act upon.
- Specifying the action(s) to be performed on those parts.
Bring up the Default Cube
- Launch Blender.
- Load the factory settings using File → Defaults → Load Factory Settings.
This should give you a perspective view of a scene containing three objects:
- a cube,
- a light source,
- a camera.
Setting up the Viewport
It will be easier to work on the roof of your house in a perspective side view:
- Press to switch to a "perfect" right side view.
puts the viewport into perspective only if it's not already in perspective. Otherwise, switches the viewport back to orthographic view.
"Right Persp" will be shown on the top left of the 3D View. The "up" (Z) direction in the scene is now "up" on your monitor as well.
It will also help to zoom in a bit:
- Make sure the 3D View window is active (which means your mouse cursor is in it).
- SCROLL or press a few times until the cube is about 1/3 the height of the viewport.
Because you just loaded the factory defaults, the 3D transform manipulator will be enabled. For mesh editing, it will help to turn the manipulator off:
- Make sure the 3D View window is active.
- Press + to toggle the manipulator on or off.
Pressonce. This puts you into Edit Mode on the selected object, i.e. the cube.
If the lamp and/or camera were selected instead of (or in addition to) the cube, you wouldn't be able to enter Edit Mode. (Cameras and lamps are edited in a different fashion.)
Here's how the cube should look at this point: