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Shadow Popping?

polycounter
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HarlequinWerewolf polycounter
I am but a simple hair artist so this may be something easy, but can anyone tell me why my shadows are popping on my hair cards? It's most noticeable on the forehead. I assume it's some kind of culling thing?  :#

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  • iam717
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    iam717 interpolator
    while you wait for someone that knows, this video speaks about hair and lighting, 
    if it helps it would be beneficial to post the solution for others.

    If i had to guess, it looks like some compensation is happening.

  • HarlequinWerewolf
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    HarlequinWerewolf polycounter
    iam717 said:
    while you wait for someone that knows, this video speaks about hair and lighting, 
    if it helps it would be beneficial to post the solution for others.


    If i had to guess, it looks like some compensation is happening.

    Appreciate the link, but these are hair cards rather than a strand groom. And I think the emissive lighting not working with strand hair is a by product of lumen. 
  • poopipe
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    poopipe grand marshal polycounter
    i forget the name of the feature but there's a specific volume shadowing option for hair cards that drops off quite early  -
    there's also a lot of options in the settings for lights that affect when certain features lod out and of course there's the thousand config options you can fiddle with. 
    that said - you're using lumen so you're probably fucked and 'it'll be fixed in the next engine version honest'

  • HarlequinWerewolf
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    HarlequinWerewolf polycounter
    Thanks @poopipe I understand now that lumen is the biggest issue here and I opened this for the first time in about a month the other day and thought, nah... we just need to start over. I'm not happy with the shader, the lighting... the whole thing so yeah, I think I'm just gonna switch off lumen  :s 
  • HarlequinWerewolf
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    HarlequinWerewolf polycounter
    For what it's worth, this has been annoying me for the last few months so I did some digging and debugging and found out that the culprit was indeed the virtual shadow maps and that I could see the clipmap/mip level issues in the debug view.
    Directional light popping:

    Debug view:


    For the directional light, I edited the .FirstLevel and .LastLevel values to have a different range. Default first level is 6 and last level is 22. I changed it to 10 and 30. 

    Now I have a consistent clipmap when zooming in and out and if I go very far it's no longer noticeable. 


    However, this caused lots of artefacts on the body of the mesh. So I decided to lose the deep shadows I was getting from the directional light and just have more flat shadows by setting .FirstLevel to around 1 and .LastLevel to around 2. This created consistent shadowing but more flat shadows.

    For the rectangle and point lights, I saw the same issue in the debug view:


    To solve this I edited r.Shadow.Virtual.ResolutionLodBiasLocal to -3. This considerably increased performance costs, but for a basic character presentation setup I'm OK with that 





    EDIT
    I ended up setting the LastLevel to 10 and r.Shadow.DistanceScale  to 100. With all the other lights on, I can't see any popping
    Current render: 



    Now, I just have to sort the noise...
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