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    #91
    Denoiser seems to work waaaay better in preview 2


    Area shadows still broken
    Stationary skylights still broken
    Indirect lighting intensity still broken
    Last edited by Arkiras; 10-06-2020, 02:58 PM. Reason: Edit, spoke too soon

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      #92
      Has anyone been successful when using IES profile with the gpu lightmass?

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        #93
        Originally posted by Prav2pkp View Post
        Getting crash error when using UE 4.26 preview1 GPU Lightmass

        Fatal error: [......
        UE4Editor_RenderCore
        UE4Editor_RenderCore
        UE4Editor_Core
        UE4Editor_Core
        ...
        ntdll
        I also had crashes with P1 and P2. Pulling the usb cable from my Oculus Rift fixed that

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          #94
          Looks like preview 3 broke gpu lightmass further...

          This bug where gpu lightmass is darker with pointlights then cpu bake... darker static gpu vs the stationary/ moveable in gpu.. is back and its worse in preview 3.. Previously changing the source radius to anything other then 0 fixed it to have the proper intensity... now not even changing the source radius fixes it. static baked point lights are way darker in gpu lightmap baker reguardless of point light radius. Way darker then stationary gpu/ moveable.... and way darker then cpu version static.

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            #95
            Good day to all. I tested GPU LIghtmass in 4.26.0 preview 4. And have some problems with UV seams on geometry. When building light use CPU i have not UV seams problem. How can solve this problem? Click image for larger version

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              #96
              Originally posted by Priest_kod View Post
              Good day to all. I tested GPU LIghtmass in 4.26.0 preview 4. And have some problems with UV seams on geometry. When building light use CPU i have not UV seams problem. How can solve this problem?
              Turn the denoiser off and use irradiance caching with a ton of samples.

              Probably faster to just fix those horrible UVs though

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                #97
                Wait a minute, i have not tested 4.26 yet, but do GPU Lightmass still require UV-s ?
                tox.chat - Skype alternative, fast C/C++, no bloat.

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                  #98
                  Yes of course... how would it work without them?

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                    #99
                    testing GPUlm in 4.26.0.p5 - any suggestions how to improve the quality? still seeing 'splotches' with these settings
                    Edit: even with denoiser - some splotches still are visible - it does look a bit better though.

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                    Last edited by maxbrown; 10-29-2020, 09:28 AM.

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                      Originally posted by maxbrown View Post
                      testing GPUlm in 4.26.0.p5 - any suggestions how to improve the quality? still seeing 'splotches' with these settings
                      Edit: even with denoiser - some splotches still are visible - it does look a bit better though.
                      I've not seen a result like this from GPU LM honestly. Only thing I could suggest is turning off lightmap compression, but that doesn't look like the issue here.

                      Otherwise you could try cranking the samples/ic quality up to the max of 8192

                      Edit: Actually I am seeing results similar to yours in areas with very low indirect lighting. If it is an option you may want to consider increasing your lightmap resolution, making the texels smaller at least makes the noise a bit less noticeable.
                      Last edited by Arkiras; 10-29-2020, 12:15 PM.

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                        maxbrown Try using First Bounce Ray Guiding with a fairly high number of trial samples

                        Edit: Setting trial samples to 25% of GI samples seems to give good results, see my reply below


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                        Last edited by Arkiras; 10-30-2020, 11:09 AM.

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                          Arkiras Thanks for the suggestions. Its looking better now although I'm getting crashes if I make the values too high (gtx1080 - maybe too old for this new tech). Will test more - also on a 20-series card.

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                            Originally posted by maxbrown View Post
                            Arkiras Thanks for the suggestions. Its looking better now although I'm getting crashes if I make the values too high (gtx1080 - maybe too old for this new tech). Will test more - also on a 20-series card.
                            I suspect trial samples uses the first X number of GI samples as guidance for future GI samples. Meaning its limited by the amount of GI samples you have, so if you set GI samples to 512 and trial samples to 512, it essentially does nothing. I'm guessing the trial samples may need to be kept in GPU memory also so perhaps that is causing the crash for you.

                            My testing seems to bear out this conclusion perfectly:
                             
                            Spoiler


                            Following that logic, I gather there is a probably "sweet spot" for trial sample count, where by continuing to increase the value just gives you a worse result because there aren't enough regular GI samples to take advantage of all the trial samples.

                            Not sure where the tipping point is (intuitively I want to say 50% as that seems to make sense), but I think it is a good idea to use the defaults as a basis for determining what to set. By default the Trial Samples are 25% of the GI samples (128 trial samples / 512 GI samples) and I find this works pretty well. So if you were doing 1024 GI samples, you'd use 256 trial samples. In my case for the comparison in my previous post, I used 8192 GI samples and 2048 trial samples...

                            First bounce also seems to have some bugs, I sometimes I get blocky artifacts and broken results between tiles. Not sure why.



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                              Hello! I'm getting this errors after the light build. You can see there are pixels on the walls. Any idea on how to fix that?

                              There are my settings:
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                              Attached Files

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                                I already tried some stuff and wanted to let you know: (lately used preview 4)
                                Had some issues with skylight and realized that it's only calculated when I change some skylight settings while baking (in preview mode; f.ex. lighting intensity +0.1). This even works when I don't activate virtual textures at all.
                                Which brings me to my second experience: Previewing is nice to have but I can only make sure that I got good FPS and no artifacts when I disabling virtual textures (I got a big scene). Maybe you know if there's another solution with better virtual texture settings? (I guess this might cause youre pixel-errors xaviprz)
                                Still I have lots of crashes and errors I don't know a lot about, but I thought it might be useful to kind of share these things with you!

                                Im using RTX 2080 TI.

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