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Feature Request Raytracing/Pathtracing - Sampling problems

Discussion in 'High Definition Render Pipeline' started by OlavAketun, Oct 10, 2022.

  1. OlavAketun


    Aug 4, 2021
    When using raytracing, more specifically pathtracing in Unity theres a really annoying problem.
    The sampling method is what I can only describe as deterministic. Meaning in a scene if you find the same camera position and camera angle and render two images at the same SPP, you will get the exact same image twice.
    It seems the sampling is not truly randomized, sure it's based on a blue noise method so there will be some blue noise texture repetition because they're generating a 128x128 blue noise texture from a method based on "A Low-Discrepancy Sampler that Distributes Monte Carlo Errors as a Blue Noise in Screen Space" by Heitz et al.
    But it's still using the same distrobution of rays every initial frame.
    Had the initial samples been shifted every time there wouldn't have been a problem, but currently we'll get the same image if rendered twice.

    Is this intentional? If so, why?
    It seems strange to want the result to be the same every time you render the same image.
    I could understand it if one could simply turn it on or off, perhaps for image sequences it would be nice but not for still images.

    Perhaps shift the bluenoise position? :confused: