White jaggies on overbrights

[particlerealities]

This is preview of an office suite I'm working on. I'm able to get rid of the white jaggies on overbright areas when using the standard renderer, but when I switch to RT Production, I can't seem to get rid of them. If memory serves, enabling Sub-pixel Mapping and Clamp Output with a value around .95 seems to fix it with the standard renderer, but the same settings don't help with GPU. Am I missing something?

Is there a better way to get rid of them?

These were rendered in about 15 minutes with a GTX 980 and a Quadro 4200 with the denoiser enabled.

[particlerealities]

I tried changing the Engine Type to CPU and the jaggies went away. Is this a known limitation of CUDA & OpenCL? How can I continue rendering with GPU while also solving the overbright white jaggies?

[particlerealities]

Bueller? Bueller? Anyone?

Perhaps I posted in the wrong section...?

[Svetlozar Draganov]

Subpixel Mapping is not supported on the GPU, that's why the result cannot be smoothed out like with the CPU engine which supports it.
The only way to fix that would be to make the light invisible and to exclude the light-geometry from the illumination, then add a secondary light source will lower intensity to illuminate the geometry only.
V-Ray should be able to sample those areas when the difference between bright and dark pixels has been reduced.

[^Lele^]

Or turn Bloom on in the VFB, on the very bright, jagged render, which will simulate what happens with energy bleeding (in our eyes, or in a camera) and give you the most believable result with the least of tweaking.
Make sure you read the docs on how to best use those controls to avoid frustrations.

[particlerealities]

Thanks fellas! Svetlozar - The light fixture has a multi-sub material, with a VrayLightMtl applied to the openings, and I have a Free Rectangle light just beneath it with an IES file attached to it. I had the intensity of the VrayLightMtl set to 30. I lowered it to 3 and the jaggies went away. Very easy solution - thanks!

Good idea about the Bloom Lele - I need to play with that feature more.