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Shading bug in HDRP

Discussion in 'Graphics Experimental Previews' started by jjejj87, Aug 29, 2019.

  1. jjejj87

    jjejj87

    Joined:
    Feb 2, 2013
    Posts:
    453
    Before I begin, I would like to put it out there that I am sure if what I observed is the intended behavior or an actual bug. Any feedback from the HDRP team would be appreciated.

    Alright, so I was making a plastic bucket in HDRP, and applied subsurface scattering. Then I noticed that there is this strange shadow line inside the bucket. It seems like the brightening up done by the transmission code is ending abruptly where the shadow is and is causing a clean shadow line instead of the smooth line. The object is a bucket, and the shadow should be smooth like on the outside of the bucket.

    transmission.jpg

    I wiggled around and changed a few things to get it to go away, but it looks like this happens regardless of diffusion profile settings, quality settings. My guess is that something in the transmission part of the subsurface scattering shading is causing this.

    Here is a version without textures.
    transmission2.jpg

    It is very "distracting" to look at and I am hoping this is something that can be straightened out and not the intended behavior of transmission in general. Unless, this is how it is in real life :)

    Any feedback would be appreciated.
     
    Last edited: Aug 29, 2019
  2. Grimreaper358

    Grimreaper358

    Joined:
    Apr 8, 2013
    Posts:
    698
    This is an issue with it. I get the shadow artifacts as well.
    Seems it's the self-shadowing

    SubsurfaceShadows.jpg
     
  3. jjejj87

    jjejj87

    Joined:
    Feb 2, 2013
    Posts:
    453
    My question is whether this is the intended outcome of HDRP or a bug.

    I hope someone from the HDRP team can answer.
     
  4. dandeentremont

    dandeentremont

    Joined:
    Jan 11, 2013
    Posts:
    22
    I've had a little success reducing this by turning down the Normal Bias in the advanced Shadow settings of the light.
    But it's never 100% gone, and it's a delicate balance to make sure the shadow acne doesn't appear.
    I assume it's a shader artifact and not the intended look. Shadow terminators have given me a lot of trouble in the past when I've tried to write my own SSS shaders.
     
    Last edited: Jul 17, 2020
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