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GPU profiling - Shadow Projection on Static lights?

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    GPU profiling - Shadow Projection on Static lights?

    Hello fellas,

    I've been learning UE4 for a few weeks now, only possible with the great ressources on the learning platform and the forums... but I need some extra help now.

    I can't figure out why the Shadow Projection is so expensive if everything on my scene is on static. Even why there is any resource dedicated to Shadow Depths. I thought that Shadow Projection and Shadow Depths are required for non-baked lighting, but every single light in the scene is on Static, and I re-built the lighting. I thought I should have 0 resources dedicated to lighting/shadows at run-time if everything is on Static... Did I get it wrong?

    There are about 30 lights that cause this. Actually it's a BP actor replicated 30 times. But why is it spending at all if the lighting is baked?? Every issue comes from this BP, so maybe I set-up something wrong? Or it got bugged because of so many tests I did?

    Please help me figure this out...

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    i don't get why ShadowDepths generates this cubemap...

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    The BP that spends most resources... replicated 30 times.
    Shadow Projection and Depths on Static lights?

    It is definitely creating shadowmaps for the point lights. Are you sure that nothing is moving and the light build is up-to-date?

    Anyway, regardless of the issue, it seems to me that you need a spot light here, more than a point light.
    Alessio Paoletti -


      I'm using an IES profile, so I thought that it doesn't matter if spot or point... anyway I just changed it and will re-bake (I did several builts before posting. So I'm sure everything is on Static, but also I'm probably missing something)


        Are you sure you don't have any other light? Like a directional or a skylight casting shadows... what is the output of stat LightRendering?
        Alessio Paoletti -


          Yes, there is a Directional Light and a Sky in the scene, and 4 spots on top of those 30... all set to static. I think something weird was happening here.

          Anyway, after changing from point(IES) to spots(IES) fixed the thing, now performance seems more like I thought it would be:Click image for larger version

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          So now I'll improve the look and add more meshes... but I was stuck on the performance. I have no idea if it was the point lights with IES, or because changing/testing so many times maybe got something bugged... I also did try raytracing this morning, and then switched back. Maybe this unbugged something also?

          but anyway, thank you Ale_32 your comment pointed me in the right direction.