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Thread: Black Spots with Final Gather...

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    Default Black Spots with Final Gather...

    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?

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    Design Visualization Moderator stusic's Avatar
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    Default Re: Black Spots with Final Gather...

    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.
    Phillip Bradshaw
    Lead Pixel Pusher, Lucid Design Studio
    CAD Detailer, Proctor Productions

    A doctor can bury his mistakes but an architect can only advise his clients to plant vines. - Frank Lloyd Wright

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    Design Visualization Moderator stusic's Avatar
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    Default Re: Black Spots with Final Gather...

    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 )
    Phillip Bradshaw
    Lead Pixel Pusher, Lucid Design Studio
    CAD Detailer, Proctor Productions

    A doctor can bury his mistakes but an architect can only advise his clients to plant vines. - Frank Lloyd Wright

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    Default Re: Black Spots with Final Gather...

    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!

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    Default Re: Black Spots with Final Gather...

    Quote Originally Posted by 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!
    Also, increasing their radius can help...
    Steve Bennett |BIM Manager
    Taylor Design | Adventures in BIM

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    Design Visualization Moderator stusic's Avatar
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    Default Re: Black Spots with Final Gather...

    Quote Originally Posted by 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!
    Glad it worked for you.
    Phillip Bradshaw
    Lead Pixel Pusher, Lucid Design Studio
    CAD Detailer, Proctor Productions

    A doctor can bury his mistakes but an architect can only advise his clients to plant vines. - Frank Lloyd Wright

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