anyone know what causes spots on a model at render time? ....I'm not talking little fuzzy AO spots.. but big whacking ones in regular patterns!

(1 infinate light, IBL with a simple white to black gradient. 1 skydome (blue). Aircraft skin setup with a simple reflection node + texture and bump map. thats it - spots appear with both Raytraced and Mapped Shadows and with no shadows. Normals forward has no effect other than to raise render times. Spots appear with ground on and off. nothing else is in the scene. this is poser 7)

Do those follow the mesh structure in any way?  These kind of look like double-sided poly rendering artifacts to me....

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Cage can be an opinionated jerk who posts without thinking.  He apologizes for this.  He's honestly not trying to be a turkeyhead.

Cage had some freebies, compatible with Poser 11 and below.  His Python scripts were saved at archive.org, along with the rest of the Morphography site, where they were hosted.

Looks like Polygon self shadowing to me.  Try playing about with Shadow Min BIas.

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ok it's not double sides... and the shadow min bias does nothing to correct them, (.spots appear with both Raytraced and Mapped Shadows and with no shadows..)
they only appear when you put a reflect node on the texture...

here's what I mean

no reflection node on the skin, raytraced shadows:

now, same shot, reflection node on the skin, set to .2 value, quality 1.

It's a problem Ziggie noticed some time ago, if the Reflect node is causing it.  Adjust your Reflect node to the following:

Quality 0.1
Bias 2.0

That should cure it.

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aha! thank you... thats much better now...