2D and 3D Materials

2D materials can be likened to paint which we attach to a primitive’s surface. For example, textures are images that are used to wrap a primitive with. If we take a sphere

and apply the following texture to it

we get

2D materials rely on uv-coordinates, i.e. a Cartesian coordinate system that describe where on the surface of a primitive the origin lies and where the X and Y axes lie.

Applying 3D materials is similar to taking a big block of that material and carving out the primitive.

Carving a sphere out of it yields

In the case of a checkered pattern, the 2d version is clearly preferable. Generally, other 3d materials won’t look as peculiar.

One distinct advantage of 3D materials is that they are easier to implement as, in order to determine their properties at a specific point, you need only xyz coordinates, which you already computed. There is no need to determine uv-coordinates.