Blender 3D: Noob to Pro/Materials and Textures

In 3D graphics, materials and textures are nearly as important as shapes. Scenes would be boring if all the objects were gray.

The material system in Blender allows you to model a wide variety of materials and how they interact with light. The next few modules will introduce the available options.

Material versus Texture

A material defines the optical properties of an object: its colour and whether it is dull or shiny. A texture is a pattern that breaks up the uniform appearance of the material. Very few objects in the real world have completely uniform surfaces. Instead most of them have patterning or variation in colour: consider the grain in a piece of wood or the pile in a carpet or the mortar in a brick wall.

Blender allows textures to influence materials in various ways, such as altering their colours. Multiple textures can interact with each other to produce interesting effects.

Other Material Settings

Additional settings you can specify for a material include shaders, ray-tracing and halo.

Shaders determine how the appearance of a material varies with the angle of the light: diffuse shaders give a non-shiny look, while specular shaders give a mirror-like finish. Blender's material settings always involve both kinds of shaders, but you can adjust a material's diffuse and specular colours separately to control their respective effects; if you set the specular colour to black, the surface will no longer produce reflections.

Ray-tracing is a technique for modeling the physical path of light through the scene. It is capable of producing exquisite reflection and refraction effects, including different degrees of reflectivity, translucency and transparency, and representing materials with different indexes of refraction. Blender provides two separate groups of ray-tracing settings, one for reflection of light and the other for its transmission through the material. You can control these settings on a per-material basis.

Halo rendering means an object no longer looks like solid matter, instead it appears to be made of bits of light. This can be used for real-world effects like fire, smoke and plasma, or to create fantasy effects with no connection to reality.

Note that reflections produced by ray-tracing are separate from that produced by the specular shader: the former are controlled by the material's mirror colour, while the latter is controlled by its specular colour.

Reflection is done two different ways because, while ray-tracing produces the most realistic renders, it is also very CPU-intensive.

Types of Textures

When you create a texture in Blender, you will see a popup menu listing a whole lot of different types for the texture. The image texture type lets you use a scanned image to texture your object: for example, you can scan an actual piece of metal and use that to give your object a realistic metallic appearance, or use a photograph of an actual brick wall to texture the wall of a building model, and so on.

The other texture types are called procedural, which means the textures are generated according to algorithms built into Blender itself. These can be useful for simulating various effects when you don’t have an image of the real material handy; they can also be applied to augment the appearance in various ways. For example:

• using a “cloud” texture to “dirty-up” a material

or

• using one texture as a stencil to create an amalgam of two other textures.

Additional Resources

• Diffuse reflection at Wikipedia.
• Ray tracing (graphics) at Wikipedia.
• Specular reflection at Wikipedia.
• Texture mapping at Wikipedia.