Blender 3D: Noob to Pro/Object Mode
|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.