White dots in water

Started by Dune, November 05, 2021, 03:02:41 am

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I can't seem to get rid of tiny white dots in water when rendering with PT. They occur when having sub-surface volume density and color, and disappear when not (see example).
There's a cirrus cloud and a thickened atmo (4). Quality of the first set to 1 (though that shouldn't make a difference), quality/samples of the atmo set to 64. Changing both settings don't make a difference.
Subdiv settings were raised to 0.5, and min highlight spread to 0.005 to have just a little blur.
Rendered with PT in architecture quality, mpd at 0.5 and AA at 6.

While writing this I realize the culprit might be robust adaptive sampler.... it may not calculate the cloud/atmo reflections in the 'murk' correctly. I'll check that out. Or raise/lower pixel noise threshold.....


Also there is an issue with subsurface scattering in PT with any sort of volume/haze, so maybe it's breaking itself when any volume is applied, because I noticed this without clouds in the sky trying to do an amazon river.

Good example of this is the transparency mask trick with glass shader is completely broken if you apply a fog layer, no matter how faint. It lights up the subsurface scattering, or transparent object, or apparently water.


Yeah, it's not perfect. The slower old sampler did a better job, but still some dottyness. I just kept the murk out for now.