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Help Wanted Having trouble reaching decent quality with Raytraced GI

Discussion in 'HDRP Ray Tracing' started by PhilSA, Mar 26, 2020.

  1. PhilSA

    PhilSA

    Joined:
    Jul 11, 2013
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    1,495
    Just did a quick little test of raytraced GI.

    My setup:
    • 2020.1b2
    • HDRP 8.0.1
    • using an RTX 2060





    The only way to get the light bounces from to floor to get to the ceiling is to set the "Ray Length" to its max value. But the results are very noisy, even with the two denoisers activated, and even if I switch to "Quality" mode. I tried tweaking every other setting I could find, but no success so far

    Moreover, when objects move, there is some extremely visible ghosting that happens behind the object


    And finally, the max possible Ray Length for raytraced reflections seems to be insufficient for this type of scene:


    • Do you have any tips for solving these issues?
    • Otherwise; can we expect huge visual improvements in upcoming releases, or is that representative of what realtime raytraced GI will be like for the near future?
     
    Last edited: Mar 26, 2020
  2. Grimreaper358

    Grimreaper358

    Joined:
    Apr 8, 2013
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    You want to be in Quality mode for the best results for both Reflections and GI
     
  3. PhilSA

    PhilSA

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    Jul 11, 2013
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    tried it, but there's barely any difference in noise amount. The only difference is when I set the Sample Count to something like 5, but then I go down to 20 fps on my pretty good PC

    However, I did reduce the size of my test scene, which was way too large. The cube in the middle of the room here is 1x1x1. Now my rays can reach everywhere


    And the movement noise is still an issue as well
     
  4. PhilSA

    PhilSA

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    It Unity's raytraced GI using RTXGI under the hood? I see Unity's SpaceShip demo being used as a demo scene on Nvidia's website so I'm guessing its integration is in the works?

     
    Last edited: Mar 26, 2020
  5. Grimreaper358

    Grimreaper358

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    That's from an early version of a Realtime GI implementation (DDGI) that Unity did a few months back.
    You can watch a talk on it here if you'd like.
     
    PhilSA likes this.
  6. Grimreaper358

    Grimreaper358

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    Depending on your card you might not be able to get rid of the noise in GI for attracting. I'm using a GTX 1080 and I get about the same amount of noise. I would expect an RTX 2060 to be a fair bit better but it's looking almost the same.
     
  7. JasonB

    JasonB

    Joined:
    Dec 29, 2010
    Posts:
    72
    I have a 1660 Ti (so, no RTX cores) and a friend who has a proper RTX card and he reports pretty much identical performance in a test project where I'm using ray tracing. Seems to indicate to me that, at least in HDRP 8.X, RTX cards aren't being utilized... period. Or the CPU usage is so high that it doesn't matter. HDRP 10.X apparently runs better, but irritatingly there's no easy way to upgrade to it. You have to pull it from github and that's annoying.

    There's another thing worth pointing out here - yes, the GI in 8.X is unusable for untextured objects because the denoiser is absolutely terrible and that noise is extremely apparent on a completely even surface. However, it looks a lot nicer when using finished/textured assets, as the textures can hide the GI noise a lot. So, a huge factor in your test scene not looking good is because your assets aren't textured so now you can make out every little imperfection in the GI.
     
  8. auzaiffe

    auzaiffe

    Unity Technologies

    Joined:
    Sep 4, 2018
    Posts:
    42
    Hello,

    Our current DXR implementation is still in preview, thus you may not be able to get a great quality for some effects (in this example RT GI as the main lighting source for your scene). This is something we are working on and we will improve in the future.

    In your precise case i'd drop the clamp value to 1.0~1.5 and increase the upscale radius of the effect.

    I'd also boost the denoiser radiuses to their maximum values.

    Tell me if that helps,
     
  9. auzaiffe

    auzaiffe

    Unity Technologies

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    Sep 4, 2018
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    I would also suggest disabling half resolution denoiser. It affect quite strongly the denoiser's quality, but helps with its performance.
     
  10. auzaiffe

    auzaiffe

    Unity Technologies

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    Sep 4, 2018
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    Also, given your scene you should probably use the extended shadow culling option available in the Ray Tracing Settings volume component (available on 9 and 10 iirc). Otherwise you will get some light leaks in your reflections and GI.
     
    PhilSA likes this.
  11. alexandre-fiset

    alexandre-fiset

    Joined:
    Mar 19, 2012
    Posts:
    469
    For the first time, with 2020.2 + HDRP 10, I have now the sample scene running at 30 FPS steady on a RTX 2060, with raytracing and directional + spot light raytraced shadows.

    This is actually going somewhere :D

    I hope it keeps getting better like this as it may end up being suitable for next gen.

     
    chap-unity and sqallpl like this.
  12. gmatthews

    gmatthews

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    Jan 13, 2016
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    Did you have to do something special for spot lights? I can get point lights working and causing shadows, but not spot lights. Am using RTX2080. Been using Unity for several years and follows ray tracing guides pretty closely but can't work out what I've done wrong
     
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