Reflection artifacts

Hi,
I got a car scene with a complex self-made carpaint shader (multilayer blend material) in a studio environment.
I programmed a “VRaySpotLight”, basically a normal spotlight with a sphere behind it which always has the same intensity than the light with a whie VRayLightMtl so this spot can now cast “reflections”, too.
Now the reflections look kinda off and I don’t know where to look for the error. See an example attached of what artifacts I mean. The shader has more than enough subdivs (256) with “divide shading subdivs” turned on and max AA samples 12.

Looks overbright to me maybe. Try using Max Ray Intensity, or knocking down the light’s multi.

I noticed setting the adaptive amount down from 0.95 to 0.85, max ray intensity to 20 and upping the max AA samples to 24 got rid of SOME of the artifacts yet not all of them. I really dont want that high AA in my scene since it will bog down everything seriously. Yet I need to have the sphere VRayLightMtl multiplier at the same as the SpotLight since otherwise it will not look right in conjunction. Nonetheless this also happens with normal VRayLights (Plane).

What the… I need to verify it again but it may actually be a bug. I started to check out my sub blend mtls to nail it down to a specific material layer via the global override material. I didn’t find anything, disabled the override material again and it renders fine oO.
Again I will verify this again but its VERY strange.

Send it off to Vlado & Co for testing.

Propably will do, but after restarting the errors are back, yet the other scene where I fiddled around with the settings and renders fine now with normal samples etc.

I used to get these when doing car work. In the color mapping menu, I always had to turn on sub-pixel mapping and clamp output to level 1.0. That helped get rid of my white artifacts. I had the type set to exponential. Turning the Adaptive DMC max subdivs up to 20 helped too.