vray 6 Light cache + interactive rendering with SSS looks different than regular render

V-Ray V-Ray for Maya Issues
1

default maya scene
Apply a VRayMtl
activate SSS translucency

A regular full render looks brighter than an interactive render.
Switching from light cache to brute force mode, the render then matches the darker interactive render, which leads me to think there’s something wrong with the light cache mode for full renders.

The issue exclusively happens in the refraction pass

1st image = light cache, regular render
2nd image = light cache, interactive render
3rd image = brute force, regular render

LC_full_render.jpg
LC_full_render.jpg952×531 83.4 KB

LC_interactive_render.jpg
LC_interactive_render.jpg952×531 136 KB

bf_full_render.jpg
bf_full_render.jpg952×531 91.3 KB

2

IPR is BF/BF by default. You can fix it by enabling the “Light Cache in IPR” option (Render Settings > IPR). Otherwise, to better match the BF/BF to the BF/LC results you would need to increase the Brute force GI depth (min. 16 as mentioned here).

3

thanks! I didn’t see the checkbox. In the “what’s new” page, there wasn’t a link to mention there’s a checkbox. I thought it just worked by default
thanks again

4

Thanks for the pointer, we can easily improve that.
We need to further improve interactivity with LC in IPR to remove the checkbox and make it work based on the GI engine selection, that’s why the checkbox is there.