Tweet
SSS and slow render times
Hey guys, I need general optimisation help with FastSSS. I am using Vray 3.30.1 and am using it for a slice of bread. I can't really share images or talk about the project at this point however, a frame is taking about 2 hours which I know is quite useless as it would not really tell you if that is fast or slow so let me share what I can and perhaps you can let me know.
- The slice of bread is a low res with displacement maps using all the normal stuff one should turn on to render displacements in vray. It has normal maps as well. I also set it to view dependent and max subdiv 6. Edge length 0.5. My scene is realistically scaled to what a slice of bread would be.
- Geometry generation is pre tessellated and texture resolution is at 8196.
- I optimize scenes based on Grant Warwicks tips, however, I believe that in my Sample Rate pass, the bread slice should be red as it should not be handled by AA? It is an extremely rough surface. So is this true?
- When I tried changing the Fast SSS shaders Specular Subdiv from 8 to 16. I took a dramatic render speed decrease but the noise in the SSS pass also dropped which didn't make sense. I thought Single scatter subd should be what deals with noise in SSS. Also, I can't see any noise in the spec pass anyway.
- I have three lights. One strong from below. People are indicating that my samples for lights would kill SSS badly. I initially optimized it such that it worked great for everything except the bread. Now I am seperating the scene so I can tweak the bread shader and settings individually. Dont seem to be shaving any time off.
- Changing fast SSS shader scale doesnt solve it
- Changing Raytraced to simple makes it look terrible and fake.
- Multiple scatter - changed to prepass-based illumination map and create new map for each frame ddidnt speed it up much or any. Cant tell.
What do I do? Whats a good optimization tutorial? I am rushing and tired and there are just too many options and possibilities. Help!
Thanks
- The slice of bread is a low res with displacement maps using all the normal stuff one should turn on to render displacements in vray. It has normal maps as well. I also set it to view dependent and max subdiv 6. Edge length 0.5. My scene is realistically scaled to what a slice of bread would be.
- Geometry generation is pre tessellated and texture resolution is at 8196.
- I optimize scenes based on Grant Warwicks tips, however, I believe that in my Sample Rate pass, the bread slice should be red as it should not be handled by AA? It is an extremely rough surface. So is this true?
- When I tried changing the Fast SSS shaders Specular Subdiv from 8 to 16. I took a dramatic render speed decrease but the noise in the SSS pass also dropped which didn't make sense. I thought Single scatter subd should be what deals with noise in SSS. Also, I can't see any noise in the spec pass anyway.
- I have three lights. One strong from below. People are indicating that my samples for lights would kill SSS badly. I initially optimized it such that it worked great for everything except the bread. Now I am seperating the scene so I can tweak the bread shader and settings individually. Dont seem to be shaving any time off.
- Changing fast SSS shader scale doesnt solve it
- Changing Raytraced to simple makes it look terrible and fake.
- Multiple scatter - changed to prepass-based illumination map and create new map for each frame ddidnt speed it up much or any. Cant tell.
What do I do? Whats a good optimization tutorial? I am rushing and tired and there are just too many options and possibilities. Help!
Thanks
Comment