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  • Caustics isolated points

    Hi all,

    I was about to resurect a very old thread (https://forums.chaosgroup.com/forum/...caustic-points) but finally decided to create a new one.

    I'm working on a scene with caustics. I get some very nice results but I have also some isolated caustic points I cannot get rid of.
    Working here with Maya 2019.3.1 and Vray V4.30.02 on windows 10

    So, I tried to find out what is causing these caustics isolated dots which kill all the effect. My scene is a cheat, I have three lights (VrayLightRect) that emit caustics, and only caustics. These lights don't affect anything else in the scene.
    Then, I have have the other lights that affect the scene, but don't emit caustics (caustics subd at 1 and multiplier at 0). As far as I understand, they shouldn't create any caustics. I have also some light materials where we cannot specify anything regarding caustics (to me, they don't generate any caustics).

    here is a crop of a render showing the caustics element:
    Click image for larger version

Name:	Caustics_dots.JPG
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    After some dozen tests trying to hide some objects and/or lights, I finally made a render without my three caustics emitting lights, and discovered that there are still some tiny little caustics dots in the render element. Could it be that lights, which have the multiplier at 0, or material lights, could still generate caustics ?
    I stripped down the scene, changed material lights into mesh lights, added vrayobjectproperties to disable "generate caustics", but nothing seems to help.

    I'm still investigating but thought I'll start to ask for some help. I cannot post the scene, but might send a stripped down scene to support.

    It would be great to find a solution for these isolated dots.

    One alternative question: Are there any huge enhancements to caustics in Vray5 (Maya)?

    cheers,

    Olivier
    www.mirage-cg.com

  • #2
    VRayLightMtls generate Caustics only in Direct Illumination mode so disable it to remove them. Setting a Caustics multiplier of 0 to VRayMeshLights seems to work fine. Try these settings and see if it makes a difference.
    Aleksandar Hadzhiev | chaos.com
    Chaos Support Representative | contact us

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    • #3
      Hi Aleksandar,

      Thanks a lot for your answer. In fact, I had one VrayLightMaterial that was in Direct Illumination, and the isolated dots seem now to be gone. I still have to make two or three tests in other Areas to be 100% sure.
      The funny thing is that the objects which had this LightMaterial attached, had also a VrayObjectProperties node attached, with "Generate Caustics" unchecked. So it seems that this had no effect on the objects when a light material is applied.
      Click image for larger version

Name:	Caustics_dots_gone.JPG
Views:	243
Size:	28.0 KB
ID:	1092581
      Attached Files
      Last edited by waaazoo; 18-11-2020, 05:05 AM.
      www.mirage-cg.com

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      • #4
        It looks like the issue is resolved. Thanks a lot.
        www.mirage-cg.com

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        • #5
          Just FYI, the 'Generate Caustics' option concerns the caustic generation of objects that have a refractive or reflective material applied, rather than lights.
          Aleksandar Hadzhiev | chaos.com
          Chaos Support Representative | contact us

          Comment


          • #6
            Yes, thank you. I figured that out. I didn't play so much with Vray caustics for now so I'm still learning.
            www.mirage-cg.com

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