Next gen lighting technologies - voxelised, traced, and everything else *spawn*

Discussion in 'Rendering Technology and APIs' started by Scott_Arm, Aug 21, 2018.

  1. Shifty Geezer

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    They might well have been. the two video's you linked to aren't valid evidence of it though.
     
  2. PSman1700

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    All those are just patents, people seem to full-fill their dreams based on some patents. I have seen it alot lately. Just because they patent something doesn't mean they will actually enforce or use it.
     
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  3. BRiT

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  4. lefantome

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  5. iroboto

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    It scales well. Works better with RT hardware IIRC viewing the demo.
     
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  6. Ike Turner

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    #1766 Ike Turner, Jun 11, 2019
    Last edited: Jun 11, 2019
  7. SlmDnk

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  8. pharma

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  9. JoeJ

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    CPU / GPU hybrid RT in World of Tanks (no DXR):

    CPU does BVH using Embree, tracing on GPU.
    BVH for 30 Tanks (each 50000 trianlges) takes 1.5ms on CPU.
    GPU does 1 rpp (vehicle shadows only - probaly also sun only) and denoising for area light.

    (BTW, pretty well explained in german without marketing BS :) )
     
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  10. Jay

    Jay
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    Works on DX11 GPUs also.
     
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  11. milk

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    Now it hit me. This is the future of next gen console games.
    Remember how CELL promised to usher in a new era of simulation/AI/physics heavy games? Remember most of it's horsepower ended up going into offloading tasks from the GPU that just could barely get the tasks devs were aiming for at 720p...
    Yeah, prepare for another 6 years of that again.
     
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  12. pharma

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    So ray traced shadows only on "intact vehicles (not destroyed ones)". Nice compromise to avoid any performance loss.
     
    #1772 pharma, Oct 16, 2019 at 4:58 PM
    Last edited: Oct 16, 2019 at 5:20 PM
  13. iroboto

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    There has been a lot of talk about moving the intersection closer to the CPU side of things on the APU. But I'm not necessarily sure, and we haven't seen that type of design before. Obviously for nvidia it's RT needs to be on the GPU, since it has no other way to get it closer to the CPU. But perhaps intersection hardware might be better closer to the CPU, I dunno.

    Being closer to the CPU I'm not sure has it's advantages either. But if you have spare cycles on CPU, perhaps it could do intersection. Many Ray Tracing farms are still CPU based as I understand it.

    There are some here that could provide much better commentary on it.
     
  14. jlippo

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    Yup, one of the better videos on ray tracing and acceleration structures.
     
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  15. DavidGraham

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    This is the video in English




    They do the BVH on the CPU, is this the same in DXR too?
    Also they limit the RT shadows to intact tanks (damaged models don't cast RT shadows), I wonder about the reason for this intact tank limitation, what's the difference between an intact tank and a damaged one RT wise? more BVH work on the CPU?
     
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  16. iroboto

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    DXR will call on the driver to perform the function. I'm not entirely sure if its possible to have the driver perform the calculation over the CPU, because which GPU vendor would write that type of driver?
    edit: answer below.
    CPU fallback layer.
     
    #1776 iroboto, Oct 16, 2019 at 6:06 PM
    Last edited: Oct 16, 2019 at 6:36 PM
  17. JoeJ

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    I knew somebody would say this. 7TF + CPU BVH build = 10 TF, haha :)

    No, NV certainly does it on GPU. I remember Exodus talk mentioning 4 ms IIRC, but they have been hidden with async compute.

    Sounds they use prebuild BVH for intact models, and likely only refit that + building top level AS. But i don't know.

    In any case, building or refitting bottom level AS is a task very well suited to GPU. Also CPU SIMD, but i assume GPU to be 20x faster. Bottom level can be a problem to saturate the GPU, and i think that's one reason why hiding it async works so well.
    Downside of CPU build would be skinning has to be done on CPU as well, but with 8 cores + AVX256 that's surely an option, especially on consoles having unified memory. If so however, hope on mesh shaders shrinks maybe.
     
  18. DegustatoR

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    upload_2019-10-16_20-20-58.png
    https://www.computerbase.de/2019-10/world-of-tanks-encore-rt/

    BVH creation and updates are handled on CPU by the driver on NV RT capable h/w (Pascal and Turing).
    Ray traversal and intersection testing through DXR is performed on SPs on Pascal and TU11x Turing and RT cores on TU10x Turing.
     
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  19. iroboto

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    So even when async call is submitted to update the BVH, it still occurs on the CPU?
    Interesting.
    Shoot, how are people supposed to figure this stuff out? Doesn't that indirectly tie your RT performance with your CPU?
     
  20. DavidGraham

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    Yeah I remember Battlefeild V requiring a much higher CPU to drive the DXR reflections.

    I have to mention, what World Of Tanks is doing reminds me a lot of NVIDIA's Hybrid Frustrum Traced Shadows (HFTS) released in games like Watch Dogs 2, Battlefront 2 and Division.
     
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