Hey there.
I created a realistic human character, setup its shaders using VRay Fast SSS2 + VRay Mtl (for reflection only) and blend them together with VRay Blend. It also has displacement map.
The problem im facing is that its taking too long to render if GI is turned on, more than 30 minutes even if there’s only 2 Vray Rectangular lights and one dome light.
How can I optimize my scene? Is there some tweaks I can use in SSS, GI and/or displacement settings?
Thanks!
The first thing I would check is Displacement Subdivision, make sure you’re not over-subdividing the mesh for the displacement. Vray’s default is 256, when often you don’t need anymore than 12. It of course depends on the size of your polys and much more, but I’ve seen it drag down renders even with the threshold properly set.
How fast are you usual times? It’s hard to know if 30min. is normal, slow or extremely slow, without knowing your settings or your machine. Can you do a test render with no sss or displacement so we can get some perspective.
Is this for a still, or for animation?
What are your primary and secondary GI types?
Irradiance cache / Light cache is extremely fast, even faster than no GI, but most likely to flicker. If this is just for a still, should be no problem. For animation it will need a lot of debugging to get rid of, and you may not be able to.
Brute force primary / Light cache secondary is very fast, less likely to flicker, easier to debug.
Brute force / brute force is slow, but no flickering.
If you add the V-Ray displacement quality settings to the mesh, you can try turning on the “static geometry” option there; it will take more RAM, but could make the rendering quite a bit faster.
Best regards,
Vlado