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Vray Caustics causing light to become invisible to reflections

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  • Vray Caustics causing light to become invisible to reflections

    I was running some experiments with reflective caustics when I noticed an odd behavior. My test scene has one small area light shining onto a wavy chrome object which is then reflecting some caustics onto the floor. The small light is set to be visible and it is not hidden. When using PPT, BDPT or Vray RT the caustics show up on the floor AND the reflection of the light also shows up on the chrome object. But when I turn on vray caustics (photon mapped) and render the scene with IM/LC or Brute Force for GI suddenly the light is no longer visible in the chrome reflections. I was hoping to start adding reflective caustics into my renderings using the photon mapped caustics, but obviously don't want to loose control over which lights are visible in reflections. Examples below:


    Click image for larger version

Name:	07 RT GPU about 8min.jpg
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    Vray RT (I think this is correct, caustics and light source are visible in chrome reflection).


    Click image for larger version

Name:	03 BDPT 2min03sec.jpg
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    BDPT (note that the light is visible in the chrome reflection, but the caustics on the floor are not).


    Click image for larger version

Name:	08 PPT no Caustics yes GI Caustics 3min35sec.jpg
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    PPT (light and caustics visible in reflection, caustics very noisy, but only ran for 3.5 min, with time noise would probably would clean up)


    Click image for larger version

Name:	01 IR LC and Caustics 0.2 1000 14min32sec.jpg
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    IM / LC with vray caustics (note light source is not visible in reflection)


    Click image for larger version

Name:	10 Brute Force and Caustics 0.2 100 6min24sec.jpg
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    Brute Force GI with vray caustics (again light source not visible in reflection).


    So I guess my question would be is there some setup that allows me to use vray caustics without loosing the reflection of light sources?
    Last edited by Rob Burns; 12-02-2013, 03:01 PM.

  • #2
    It looks either like a bug, or like a limitation; but you can always precalculate the photon map, save it, and then turn caustics off for the light.

    It is interesting that the GPU handled this best

    Best regards,
    Vlado
    I only act like I know everything, Rogers.

    Comment


    • #3
      Hello,

      Can you provide this scene , and inform us about Vray and Max versions you are using.
      Here is the result of my tests - the reflection of the light is visible in the chrome object.
      Click image for larger version

Name:	castics.jpg
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ID:	846905caustics.zip
      Svetlozar Draganov | Senior Manager 3D Support | contact us
      Chaos & Enscape & Cylindo are now one!

      Comment


      • #4
        sure, I just emailed the scene to support@chaosgroup.com, is that the best way to get it to you? Software versions are Max 2012 and Vray 2.45.01. And yes RT GPU is very fun to use, the new CUDA option is great.
        Last edited by Rob Burns; 14-02-2013, 12:05 PM.

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        • #5
          Thank you very much for your feedback and the scene.
          We managed to reproduce the issue - it seams that the problem is not with reflection of the light but with specular, and it only happens if Plane Light is used.
          The issue doesn't occur if Vray Sphere light or any other Vray Light is used instead of Plane.
          As a workaround you can use either Sphere Lights or you can use Vray Mesh light and assign simple plane object into it - it will work just like Vray Plane Light.
          We will update you as soon as we have a solution to this issue.
          Svetlozar Draganov | Senior Manager 3D Support | contact us
          Chaos & Enscape & Cylindo are now one!

          Comment


          • #6
            Thanks for the reply, mesh lights will work just fine for me for now, appreciate the help!

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