Materials system
In Computer graphics, Materials are an enhancement of texture mapping (and a pre-requisite for advanced shading effects) that allows for objects in 3D modelling packages and video games to simulate different types of materials in real life. They are typically used to enhance the realism of polygon meshes and other forms 3D model data.
They associate additional properties such as: advanced rendering parameters (e.g. specularity, BRDF); physics behavioural properties (such as friction, density); or sound triggers alongside texture information for surfaces. For example, if a texture makes an object look like wood, it will sound like wood (if something hits it or is scraped along a surface), break like wood, and even float like wood. If it was made of metal, it will sound like metal, dent like metal, and sink like metal. This allows more flexibility when making objects in games.
Such materials are also of value for procedural generation, where a high level description of an model may be augmented with layers of processing to produce a more detailed result (e.g. adding weathering or vegetation). Material properties may also be tied to animation channels to exhibit time dependant behaviour.
A materials system allows a digital artist or game designer to think about objects in a different way. Instead of the object just being a model with a texture applied to it, the object, or part of the object, is made up of a material.
Examples of major materials found in a video game might be: wood, concrete (or stone), metal, glass, dirt, water, and cloth (such as carpeting, curtains, or clothing on a character with skeletal animation).
Definition
Materials may be stored as part of a 3D model format or in separate material definition files (such as ".mtl" files associated with Wavefront .obj).