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vray clippers multiplies render times by 4 on a complex scene.

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  • vray clippers multiplies render times by 4 on a complex scene.

    Hello
    i unarchived a max2021 + vray 5 scene and update it to max 2024 + vray 6.20
    this scene is quite heavy (~55Go peak Ram usage)

    on my reference computer the scene took 1h23min to render (6000x3000) with vray 5
    now it takes more or less 7 hours. (same sampling, same size, same assets etc.)

    what have you done to vray guys ?

    After some investigations, i found vray clipper is guilty.
    I join two pictures.
    here there is no clipper (!)
    Click image for larger version

Name:	clipper01.jpg
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    but here the whole scene is "behind" a vray clipper.
    Click image for larger version

Name:	clipper02.jpg
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ID:	1205321
    I can see the number of unshaded rays increased a lot. Ok i suppose it's normal. Each ray has to check wether it is clipped or not.
    But what is less normal, is why vray 5 was able to render my scene within 90 minutes when vray 6 needs more than 400 minutes !
    What have you done to the clipper ?

    In this simple example i have "only" a 50% render time increase, but on a real production ready scene, it's a x4...
    99% of the rays shot by vray are unshaded rays.

    i have an "old" computer with vray 5.20.02
    Click image for larger version

Name:	clipperVray5.jpg
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    the render time is pointless since it's not the same cpu. What is important on this picture is i have only 6754 unshaded rays Vs 37 844 452 (lol it's a 5 603 factor)

    Could you please send me the old vrayclipper.dlo ?
    well seriously, is there a workaround and what changed behind the scene between vray 5 and 6 about clipper ?
    Attached Files

  • #2
    Hi, thanks for posting. Is that Chaos Scatter? Have you tried to test without scatter but other geometries with lots of polygons?
    I am not able to reproduce this issue in a simple scene consisting of Chaos Scatter (cosmos assets) and a V-Ray Clipper.
    Could you send us your scene for a test? You can do that here or trough our support contact form.
    Vladimir Krastev | chaos.com
    Chaos Support Representative | contact us

    Comment


    • #3
      Hello
      thank you for your quick answer.
      i prepared two clean scenes with instanced teapots. One rendering using 6.2.0 and the other using 5.2.0. There are 10 times more unshaded rays with 6.2.
      Here a sample screen of an unfinished rendering of my production scene. As you can see, >97% of the total raytracing is unshaded. If i remove the clipper, the scene renders fast. But my customers ask for it. As a workaround, i will use native 3dsmax slice to remove geometry before rendertime.
      Click image for larger version  Name:	prod.jpg Views:	0 Size:	134.8 KB ID:	1205356
      I send scenes to support, tyvm
      ++

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      • #4
        Hi, after a lot of tests I can confirm that VRayClipper in V-Ray 6 is rendering slower. The issue is reported as a bug under VMAX-14100 in our system.
        Vladimir Krastev | chaos.com
        Chaos Support Representative | contact us

        Comment


        • #5
          I'm glad I found this thread. I was using VRayClipper to reveal parts of a building and was getting render times of 00:12:49 per frame. Deleting the VRayClipper modifiers from the scene to render the post-reveal frames knocked my times down to 00:01:28!
          Andy Davenport
          3D Animator|Compositor|VFX Artist
          Glitch VFX Ltd
          www.glitchvfx.com

          Comment

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