Notiusweb wrote:Wallace - can I stack layers indefinitely with Composite???!!!!!
Please say YES!!!!!
Yes.
Here're the differences between layered material and composite material.
1. Composite material works like traditional mixed material, where you stochastically sample one of the layers and evaluate it.
2. The above means that you only evaluate one layer at each bounce intersecting a surface, so it's much more lightweight. The layered material evaluates the entire stack all at once to calculate the correct attenuation between layers and also combines the contribution of different BRDFs. This makes it less noisy.
3. Composite material weights the layer using a user-specified texture, you can use things like fresnel node to weight a specular material on top of a diffuse material, but this is less accurate than layered material. This is because layered material uses actual fresnel (i.e. microfacet fresnel with half vector) for actual weighting and attenuation.
So if you do things like 10 diffuse decals, then you don't really care about the accuracy of weighting of layers and attenuation, and in that case you should use composite material.