What I'm wondering about Poser IDL is whether there is any kind of bias (similar to that on lights) that is in operation.
I've been encountering issues with close fitting clothing lately where there's transparency involved - resulting in black artifacts. Changing the bias on regular lights doesn't cure the problem so I guess it's an IDL  issue.
I tried adding displacement to the clothing and even scaling it slightly to increase the distance between it and the figure that cured the IDL artifacts but that resulted in unrealistic shadowing from my main light.

 

PoserPro2014(Sr4), Win7 x64, display units set to inches.

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