GPU Ray-tracing for OpenCL

Discussion in 'Rendering Technology and APIs' started by fellix, Dec 27, 2009.

  1. Dade

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    You have to run the application with administrator rights in order to allow each thread to set its own priority. However it is more a warning than an error, it works better if GPU feeding threads have higher priority than CPU native threads but the difference shouldn't be dramatic especially with only one GPU.
     
  2. CarstenS

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    straaljager,

    With the new 1.02 Beta2, I'm getting the same error as cho, despite having the brandnew 197.41 WHQL with Cuda 3.0 installed.

    Version 0.7a runs "partially" fine though.
    For chess, I'm getting 12.75 MSamples/sec., for spaceship 15.96.
    But I'm afraid the render output for chess is somewhat broken:
    [​IMG]
    Spaceship looks normal I think.
    [​IMG]
     
  3. straaljager

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    Thank you very much CarstenS!

    If by broken render output, you mean the white dots in the image, that's perfectly normal for the algorithm being used (brute force pathtracing) and is commonly referred to as "fireflies". Currently they can be removed in postprocessing, but there are algorithms being developed (like Metropolis light transport) that don't exhibit these fireflies.

    Thanks again for taking the time to do this bench.
     
  4. straaljager

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    Forgot to mention: octane performance is about 3.20 - 3.70 MSamples/sec for the spaceship scene on a GTX260 (same demo version, same camera view). So GTX480 is about 4.5x faster than GTX260 in path tracing.
     
  5. CarstenS

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    Ah - good to hear that my card isn't broken then! :)
    And it's also interesting to see, that Nvidias claims wrt raytracing/pathtracing performance are somewhat reproducible with code that's not their own, too!
     
  6. trinibwoy

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    Works fine on my 285, and I'm only on 196.34 drivers so I'm not sure why 197.13 is required. Anyway, the 1.02 version is much faster than the 0.7 on both scenes.

    Spaceship
    v0.7 - 7.3 MSamples/sec
    v1.02 - 17.2 MSamples/sec

    Chess
    v0.7 - 6.0 MSamples/sec
    v1.02 - 13.4 MSamples/sec

    [edit] upgraded to 197.13 and now v1.02 crashes on startup, restored 196.34 and it's good again.
     
  7. straaljager

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    Hi, the sudden boost in performance you see in v.1.02 is because this version uses direct lighting to render instead of pathtracing by default (v.07a uses pathtracing by default).

    To change to pathtracing, you must double click on the button "Preview Configuration" in the Graph editor, then click once on the button "Mesh Preview Kernel" and in the right-panel change "directlighting" to "pathtracing" in the drop-down list. You'll see that Megasamples/sec will halve.
     
  8. trinibwoy

    trinibwoy Meh
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    Ah, thanks :) I'm still seeing higher performance though (slightly in chess but significant in spaceship). Are there any other settings that differ between versions that could affect performance?

    chess - 6.13 MSamples/sec
    spaceship - 11.7 MSamples/sec
     
  9. straaljager

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    There have been some performance improvements in v.1.02 over v.07a and mostly extra features, but the path tracing algorithm has stayed the same afaik, so the render output of the default scene should be identical.
     
  10. cho

    cho
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    new octane demo version :

    [​IMG]
     
  11. straaljager

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    Wow, 24 MSamples/s :grin:. But I don't think you're using path tracing. There's a video that shows how to set up this benchmark scene here: http://vimeo.com/10699771 . You should use physical sun and change the material to glossy. When all the changes are applied and path tracing is used the samples/s on the gtx480 should be 4.1 Msamples/s.
     
  12. Dade

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    It is just me or there are a load of artefacts (i.e. black triangles) :?:
     
  13. straaljager

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  14. straaljager

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    I've found the error: you have to check the box "Enable" at "State" to get rid of the black triangles. Watch this video around 0:15 http://www.vimeo.com/10699771
     
  15. Arnold Beckenbauer

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    Works fine with Stream SDK 2.1. :smile:
     
  16. Dade

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    Oh, good news :wink:
     

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