GI splotches and VrayDisplacement

[themaxxer]

I encountered some problems with displacement and GI (IM/LC)

image 1 has no displacement at all and generate no splotches...


image 2 has displacement and generates splotches at the edges of the plane...

a side note. the displaced plane is excluded from GI.

what causes the splotches?

best regards
themaxxer

[MHolmstrom]

Try using different GI Surface IDs for the objects that get splotchy.

GI surface ID - this number can be used to prevent the blending of light cache samples across different surfaces. If two objects have different GI surface IDs, the light cache samples of the two objects will not be blended. This can be useful to prevent light leaks between objects of vastly different illumination.

[themaxxer]

thanks for the tip, but it doesn't work! I have made different tests and with IR/LC there's no solution for the problem, only with BF/LC there are no splotches.
and the splotches doesn't come from the LC calculation.

best regards
themaxxer

[devin]

I'm having the same problem I think, the blotches go away once I switch to BF/LC.

[3DMK]

Why are you turning it off to GI?????

If it is because the displacement is slowing down render times too much then turn OFF displacement & do your GI prepasses then reload GI prepass & turn displacement back on.

If your displacement is quite fine you will usually not even tell the difference between having the displacement on or off during GI calculation.

Hope this helps

[themaxxer]

Why are you turning it off to GI?????

because I get even more splotches if it's not excluded from GI.
but I have also tried it with GI on and I get the same issues.

best regards
themaxxer

[MHolmstrom]

Have you tried if IR/BF creates similar leaks?
You didn't post your IR/LC settings, but I think decreasing LC interpolation samples and sample size and increasing it's subdivs could reduce the leaks a lot. Test these settings with LC set as primary AND secondary bounces to make sure there's no leaks or excessive noise.

If you're still stuck, I could take a look at your scene in case there's something you missed.