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0 opacity proxies still seen by VRayFastSSS2 rays

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  • 0 opacity proxies still seen by VRayFastSSS2 rays

    We're hitting an issue where some V-Ray proxies which have an object opacity of 0.0 are still being seen by rays cast by VRayFastSSS2. This makes sense for surfaces with opacity > 0 when simply doing a hit test for raytraced multi-scattering rather than a full shader evaluation at ray intersection. With object opacity at 0.0, most objects are completely excluded from the ray hits. The problem is that when we do get a ray hit, we get dark "shadows" in our subsurface. What's particularly bizarre is that some V-Ray proxies function fine with object opacity set to 0.0 and some act as if they're still > 0 even though they're not. The original meshes from which the V-Ray proxies in question were created also function fine, so something is happening either with the creation of the VRP or with how it's being used in 3ds Max.

    An example of a simple setup with four objects, two of which are VRPs and two of which are native geometry:
    Click image for larger version

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    Our settings for the VRayFastSSS2 shader:
    Click image for larger version

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    Any way to work around the issue with VRPs or a way to make VRayFastSSS2 better handle hit tests on almost-transparent surfaces?

    We're using V-Ray 3 and 3ds Max 2014.

  • #2
    Hi,

    Is it going to work if you move the problematic proxy objects along "z" with very small value (0.001)?
    Tashko Zashev | chaos.com
    Chaos Support Representative | contact us

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    • #3
      Slight adjustments to vertical position don't have any appreciable effect. Moving the VRP up in Z by several feet (these files are in inches) does remove the issue, but we can't reposition objects by such a large amount and retain the necessary visual composition.

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      • #4
        Then it will be better to check the files and find the reason for this odd proxy behavior.
        Is it possible to send the scene to our support mail support@chaosgroup.com ?
        Tashko Zashev | chaos.com
        Chaos Support Representative | contact us

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        • #5
          Absolutely. I will package up and send to you maƱana.

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          • #6
            Support Ticket Opened [#486132]

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            • #7
              Thanks for the sharing but unfortunately the link is either broken or the file is removed.
              Please upload the file to our FTP server - I've just replied to the ticked you've opened and you can find the log in credentials there.
              Svetlozar Draganov | Senior Manager 3D Support | contact us
              Chaos & Enscape & Cylindo are now one!

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              • #8
                The test file has been uploaded per your instructions.

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                • #9
                  This issue has been fixed and the patch is available in the latest Nightly Build from 2014-08-28.
                  Svetlozar Draganov | Senior Manager 3D Support | contact us
                  Chaos & Enscape & Cylindo are now one!

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