So I’m having issues with the ‘rest’ attribute of the lightmix. With cpu its fine, but with gpu i have to turn off ‘rest’ to match the renders. For me it seems to have something to do with the rectangle light directional attribute, but who knows.
Ive attached scene and a video can be seen here
This is vray 6.12, 3dsmax 2023
lightmix_rest.zip (58.8 KB)
I managed to reproduce the issue on a simple scene. I’ll write back with more information.
EDIT: The issue stems from the fact that there’s a mismatch between the RGB and a Full VRayLightSelect when a VRayLight has directionality active. Logged the issue (internal bug-tracker id: VGPU-6335).
EDIT2: Edited cause of issue.
thanks for info, does that mean turning it off is ok?
Yes, the images between CPU and GPU should be identical when disabling Rest.
Hi, so im still wondering about this ‘rest’ channel, Ive attached another scene and also a gif. In the gif im turning off all the lights and in the rest channel you can still see the sun cast. Also whilst im at it, when i turn off the sun, you can still clearly see the noise in the area where the sunlight hits the wall…is this expected behaviour? The reason i ask is that i noticed the denoiser was leaving artifacts from this, when setting the sun lightmix value to zero.
lightmix_sun.zip (4.84 MB)
This turned out to be a GPU-specific issue: VRaySun plus a camera with a high exposure yields differences between the RGB and the Sun’s LightSelect. Logged it (internal tracker ID: VGPU-6928 ) for dev investigation.
This happens because of the different noise levels of the sunlit and non-sunlit areas, which is expected. It’s especially visible in short renders. Basically, you need more samples. Making the sun larger, to create softer lighting/shadows, may help the denoiser to clear it up.
thanks for reply, much appreciated.
hiya, is there any update on this issue at all?
No movement, I’m afraid. Will add a bump on your behalf.
thanks bud 