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Lightmass: multi-bounced sky lighting

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    #16
    Great job Luoshuang, as usual.

    This is something I intend to implement in Lightmass when I get a chance. I will take a look at your implementation and see if there's anything I can reuse when I do so. Unfortunately I am pretty overwhelmed these days with other tasks so it will be a while. I'm planning to reuse the rays from the first bounce for subsequent bounces, so that multiple bounces effectively don't cost extra, which is an artist expectation with Lightmass at this point.

    Also, skylight needs better directionality on the sky light source, right now it's reduced to a 3 band SH which is like an extremely low res cube map, all directionality is gone.

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      #17
      Originally posted by DanielW View Post
      right now it's reduced to a 3 band SH which is like an extremely low res cube map, all directionality is gone.
      Is that why it's hard to get good directional shadows from a strong bright spot in a skylight?

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        #18
        Originally posted by Wilkes View Post
        Is that why it's hard to get good directional shadows from a strong bright spot in a skylight?
        Yes. However, without a robust importance sampling strategy, that kind of cubemaps can easily cause a lot of noise.

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          #19
          Originally posted by DanielW View Post
          Great job Luoshuang, as usual.

          This is something I intend to implement in Lightmass when I get a chance. I will take a look at your implementation and see if there's anything I can reuse when I do so. Unfortunately I am pretty overwhelmed these days with other tasks so it will be a while. I'm planning to reuse the rays from the first bounce for subsequent bounces, so that multiple bounces effectively don't cost extra, which is an artist expectation with Lightmass at this point.

          Also, skylight needs better directionality on the sky light source, right now it's reduced to a 3 band SH which is like an extremely low res cube map, all directionality is gone.
          Hi Daniel

          Beside this, I found a bug in the indirect path driven photon emission: https://forums.unrealengine.com/show...or-spot-lights

          Hope the bug won't add a lot of extra work to you

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            #20
            Will this also work with swarm agent? Do other clients need the same exe locally?

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              #21
              Originally posted by Norman3D View Post
              Will this also work with swarm agent? Do other clients need the same exe locally?
              SwarmAgent always distributes the UnrealLightmass.exe on the master to others.

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                #22
                Originally posted by Luoshuang View Post
                SwarmAgent always distributes the UnrealLightmass.exe on the master to others.
                This is seriously awesome. I've had so much trouble with indirect lighting in lightmass that I have almost given up, I'll give this a run on my scenes

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                  #23
                  Incredible work man! The lighting travels so beautifully, it looks like Pixar's renderman!



                  I did some tests from the current scene that I have been working on. The setup was Directional + Skylight.
                  The rendering time was about 3x times faster with a better samples deifinition.
                  I have noticed some bugs coming from the directional lighting.

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                  I will do more tests when I get some time!
                  Attached Files
                  Last edited by rafareis123; 03-21-2017, 04:04 PM.
                  http://www.ue4arch.com

                  https://www.youtube.com/channel/UCjp...pois6WVG6hqXNQ
                  Latest projects

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                    #24
                    Originally posted by rafareis123 View Post
                    Incredible work man! The lighting travels so beautifully, it looks like Pixar's renderman!

                    I did some tests from the current scene that I have been working on. The setup was Directional + Skylight.
                    The rendering time was about 3x times faster with a better samples deifinition.
                    I have noticed some bugs coming from the directional lighting.


                    I will do more tests when I get some time!
                    This is amazing, to be clear, you got that performance improvement without doing any setting changes between the two versions? How many bounces were you using?

                    EDIT: Removed images from quote
                    Last edited by Norman3D; 03-21-2017, 04:50 PM.

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                      #25
                      Originally posted by rafareis123 View Post
                      Incredible work man! The lighting travels so beautifully, it looks like Pixar's renderman!

                      I did some tests from the current scene that I have been working on. The setup was Directional + Skylight.
                      The rendering time was about 3x times faster with a better samples deifinition.
                      I have noticed some bugs coming from the directional lighting.

                      I will do more tests when I get some time!
                      Thanks! Waiting for more results from you to identify bugs more clearly.

                      Originally posted by Norman3D View Post
                      This is amazing, to be clear, you got that performance improvement without doing any setting changes between the two versions? How many bounces were you using?

                      EDIT: Removed images from quote
                      I think that is because the scene's contrast in lighting is reduced by multiple bounces, then we need fewer adaptive refinement levels to achieve a good result.

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                        #26
                        [MENTION=12653]rafareis123[/MENTION] [MENTION=47093]Norman3D[/MENTION]

                        Bad news: I found a bug that causes all lights to lose their first bounce (second and later on are preserved) The 4.15 binary is updated, please redownload it and try again.
                        Last edited by Luoshuang; 03-21-2017, 09:56 PM.

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                          #27
                          Hi, awesome results with this!

                          Any help on how to implement this? I did a quick search and couln't find out where or how should I use the file.]


                          Thanks

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                            #28
                            Originally posted by maxdaiber View Post
                            Hi, awesome results with this!

                            Any help on how to implement this? I did a quick search and couln't find out where or how should I use the file.]


                            Thanks
                            Replace UE_4.15\Engine\Binaries\Win64\UnrealLightmass.exe with the provided one.

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                              #29
                              The lost first bounce is now fixed.

                              Before fix:
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                              After fix:
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                              With a directional light:
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                              Last edited by Luoshuang; 03-21-2017, 08:05 PM.

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                                #30
                                Even better! Is the issue you linked to before with the spotlight also fixed? Or is this something you can't properly fix on your side? Would you advise to avoid using spotlights if possible for our bakes?

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