Black Spots with Final Gather...

[kms.118789]

Using Mental Ray (VIZ) I did several test renders and they appear to come out fine, however when I did a finished rendering using final gather there is one area were there appears black spots. Has anyone seen this, and how do I resolve this? I'm using GI as well and have adjusted the photon map accurately in the test renders. Does this have some residual affect on the FG process?

[stusic]

There are a bunch of things that can cause these spots. Most often though *I think* it's from Reflect/Refract maps; if you have those, try changing them to Raytrace maps...

Are these spots in low-light areas? This can be compared to a digital camera whose sensor can't detect enough light to get a clear snapshot. Are you using Logarithmic Exposure Control? That can create artifacts also.

[stusic]

It also occured to me that you may need to adjust the number of photons per sample and/or the average GI photons per light. (if the above solution is not actually a solution )

[kms.118789]

So I'm not sure which one, or combination of, fixed the problem, but I increased the photons, increased the "samples per pixel" and samples in the FG rollout...and no more spots...
Thanks!

[Steve_Bennett]

So I'm not sure which one, or combination of, fixed the problem, but I increased the photons, increased the "samples per pixel" and samples in the FG rollout...and no more spots...
Thanks!

Also, increasing their radius can help...

[stusic]

So I'm not sure which one, or combination of, fixed the problem, but I increased the photons, increased the "samples per pixel" and samples in the FG rollout...and no more spots...
Thanks!

Glad it worked for you.