Serious specular bug

[Moriah]

This is a normal plane, standard ggx shader with some reflection and glossiness, and a few vray lights around it. The lights are a bit thin, 2cmx40cm. When rendering it appears like this.
It seems like there's a specular cutoff going on or something. Tried other brdf's and same thing happens. It's caused by specular cause it only appears on spec pass. Reflection is barely visible

Any ideas?

[instinct]

This is most likely due to the reflection cutoff. From the docs:

Cutoff– this is a threshold below which reflections/refractions will not be traced. V-Ray tries to estimate the contribution of reflections/refractions to the image, and if it is below this threshold, these effects are not computed. Do not set this to 0.0 as it may cause excessively long render times in some cases.

You can find it in the options rollout.

Cheers,
Thorsten

[piotrus3333]

cutoff value is in VRayMat settings. 'options' tab.

[Alex_M]

What is the "Cutoff" of the material set to (in the Options tab)? Try setting it to "0".

PS: Seems like we've all posted at the same time

[Moriah]

I tried several values, even 0, no difference. That was my initial thought but no.

EDIT: The cutoff parameter only affects the reflection itself, not the specular btw...

[dlparisi]

Check the cutoff value on the walls as well, not just the floor (basically anything that gets reflected by the floor on a path to the lights.)

[instinct]

What about the cutoff in the lights? (found in the samplings rollout)

[Moriah]

What about the cutoff in the lights? (found in the samplings rollout)

That worked! Didn't even remember that lights also had cutoff values... Thanks everyone

[vlado]

It's somewhere on the "to do" list to make the light cutoff somewhat more gradual.

Best regards,
Vlado