Material (3D computer graphics)
A natural material is defined in 3D computer graphics either by constant color values or textures . Some techniques are real-time capable, other methods are reserved for realistic rendering programs due to the complex calculation processes.
The following material properties are considered real-time capable, as they are supported by most graphics cards in Gouraud Shading :
- Ambient lighting describes the object color by a constant value and simulates the indirect lighting from the environment.
- Diffuse lighting describes the effect of a matt surface from which the light is emitted evenly in all directions.
- Specular Lighting : It is possible to set in which angle range, how strongly and in which color a body reflects the light from a light source. An almost real-looking reflection is generated by a texture whose texture points result from the viewer's point and surface normal vector according to the law of reflection.
- Emissive lighting describes the self-lighting of objects such as lamps.
- The transparency describes the transparency of a material.
Not real-time capable (even if they are increasingly supported by the latest graphics cards) are:
- Bump mapping describes the surface relief using a texture.
- Displacement mapping .
- Reflection is simulated either by reflection mapping or ray tracing .
- Refraction (light refraction) in the material.
- More complicated lighting models .
- Light scattering in the material.
The exact names can change from program to program.
It should be noted that the techniques used are pure reproductions of visual effects that only create the illusion that actual light properties are being reproduced. In fact, the algorithms used are only based to a small extent on the physical behavior of light in interaction with matter.
literature
- Alan Watt: 3D Computer Graphics, Chapter 8 (pp. 223-262). Pearson, Harlow 2000, ISBN 0-201-39855-9