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Rendering problems: An issue with Subsurface Shader (specular ripples?) and a more general issue

Joe827Joe827 Posts: 225
edited December 1969 in The Commons

Hi.

Issue Number 1:
I've been slowly introducing Subsurface Shader into my scenes with pleasing results. However, I've recently encountered something odd. When rendering a figure with "sweaty" skin, I get what appear to be ripples in the specular highlights. These do not appear when rendering up close, but when pulling back, they start to appear. Note the difference between the images on the right and left. The image on the right's specular highlights are smooth.

Relevant (or so I think) Render & Subsurface Settings:
Displacement = 0%
Bump = 0%
Specular Noise Density = 0%
Specular Noise Strength = 0%
Subsurface Shading Rate? = 4.00
Daz Overall Shading Rate of Image = 0.5

The above are all currently set to zero percent because when I first encountered the issue, they were the first dials I changed to try and fix. Does anyone have a clue what might cause this? My scene has 12 lights. 6 are shadow casting. Issue occurs with both raytrace and deep shadow map. Any ideas?

Issue Number 2:
In scenes with more ambitious lighting (several shadow casting lights and several ambient lights) I will occasionally get "glitches" in the render. You can see this on the right arm of the figure on the left. It happens randomly with or without Subsurface shader. Any idea what might be causing these?

Test28.jpg
1252 x 842 - 194K

Comments

  • jestmartjestmart Posts: 4,449
    edited December 1969

    Make sure the Shading Rates setting and Shading Scales settings are the same for surfaces with the same Group ID #.

  • Joe827Joe827 Posts: 225
    edited December 1969

    jestmart said:
    Make sure the Shading Rates setting and Shading Scales settings are the same for surfaces with the same Group ID #.

    Thanks. This resolves issue #1. I'm still working on eliminating Issue #2.

    Much appreciation for your help.

  • MattymanxMattymanx Posts: 6,902
    edited December 1969

    Those glitches are caused by Shadow maps. Switch to raytraced shadows. It will render faster with raytraced shadows anyways.

  • Joe827Joe827 Posts: 225
    edited December 1969

    Mattymanx said:
    Those glitches are caused by Shadow maps. Switch to raytraced shadows. It will render faster with raytraced shadows anyways.

    As I mentioned above, I get these with both shadow maps and raytraced shadows, but only when the lighting is complex. Also, your comment about raytraced shadows being faster puzzles me. Raytracing shadows has always been slower than shadow maps for me.

    -Joe

  • Joe827Joe827 Posts: 225
    edited December 1969

    Mattymanx said:
    Those glitches are caused by Shadow maps. Switch to raytraced shadows. It will render faster with raytraced shadows anyways.

    As I mentioned above, I get these glitches with both shadow maps and raytraced shadows, but only when the lighting is complex. Also, your comment about raytraced shadows being faster puzzles me. Raytracing shadows has always been slower than shadow maps for me.

    -Joe

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