Bug : Refraction + invisible light = artefacts

[bigbossfr]

Hi,
I found another bug :
- create a VrayRec light, set the light invisble
- create a cube behind
- attach a VrayMtl on the cube, with refraction, and refracton to affect "all channels".
- add a zdepth renderElement

Render.





I have a lot of artefacts in my Zdepth pass, my Zdepth is wrong.

Thanks.

[tashko.zashev]

Hi,
it looks like an anti-aliasing problem, do you use "Filtering" for zDepth ?
do you get same result when increase the minimum subdiv's for Adaptive DMC sampler?

[bigbossfr]

Hi,
I disable "Filtering", "clamp" for Zdepth, the bug is always here.
I have the same bug with DMC to 2-12, 0.007.

Ps : we have invisible lights in the "coverage" renderElement also. I do not understand why we have "aliasing information" from hidden objects (?).

[alainfx]

I do not understand why we have "aliasing information" from hidden objects (?).

V-Ray treats invisible geometry as fully transparent, and if there are too many transparent layers, it will give up tracing a ray.
It's a problem that we usually see in Fur, which we fix by increasing this :
Render Settings-->VRay-->Global options-->Max transparency levels

[bigbossfr]

I know Vray treats invisible geometry as fully transparent. The problem is in the "coverage" pass.
We see invisible light into this renderElement. I setted the Max transparency levels level to 1000, the light is always in the coverage renderElement...
But it is another problem.
The first problem is more "serious" because we can not use the Zdpeht renderElement properly.

[bigbossfr]

Any news about this please ?

[vlado]

It seems to work fine if filtering is enabled for the z-depth element. I'm still looking into it though. I guess the problem is that the light is invisible and therefore does not generate render elements, but on the other hand it is visible in the refractions, and because of the "Affect all channels" option, needs to generate render elements...

Best regards,
Vlado