when using a 2sidedMat in the scene, for example for curtains or grass, it takes ages to render the prepasses. I think because vray is scattering the light rays trough the material. often this is not necessary.
is it possible to make a “fast 2 sidedMat” without the physically correctness? a don’t affect GI button or something like the fastSSS2Mat combined with a prepass.
this would be very useful.
best regards
themaxxer
Can’t you use an OverrideMtl to override for GI ?
Regards,
Thorsten
It is possible to optimize the 2-sided material a lot for GI calculations, which we are working on. It’s much simpler than adding other hacks 
Best regards,
Vlado
Hello
I’m curious about your solution Vlado.
Did you aplied it to vray builds?
My problem is that rendertimes without vray2sided curtains are about 14min and with vrar2sided curtains about 75min
How to speed-up vray2sidedmtl GI calculations ?
Best regards,
Greg
I honestly can’t say I’ve ever really noticed a big difference in render times with the 2sidedmat, but any speed increase you can get me is always welcome.
I always use an override material so that reflections and GI are different.