Is there any way to detect crevices? Normally I do this with masks that I extract from the rock textures, but now I have a setup where this is hardly possible. I tried it with the merging of two distribution shaders, limit maximum and limit minimum, with not much success.
At the risk of talking complete nonsense: is it possible to use the information from GI surface details to do this? The only way I can think of is to use a render with exaggerated GI surface details via camera projection but then I inevitably get stretching.