Hi,
it means that:
- if you use a single slab with input that in the end corresponds to one of the existing Shading Model, then it is expected to have similar performance to the non substrate path. You can see what shading model it maps to when using the pixel debug tool.
- If you use new or more complex features (sss, cloth, dual spec. specular lut, glint, F90, etc.) on a slab then cost will increase accordingly.
- Then if you have N slab output by a material, you will pay N times the cost of lighting (Direct and GI) as of today. And you will pay for more GBuffer memory to store more slabs. To mitigate that later we want to experiment with stochastic lighting but this is WIP and not short term.