My GC detection trick does work. The trick there is to have a SimpleColor node with middle-gray RGB(128,128,128) in it and compare that to the number .5. If render GC is on, the measured value will be less than .5. When middle-gray is less than .5 I disable the shader GC.

The problem is that shader GC is enabled (correctly) but it affects the indirect diffuse lighting pre-calculation. Objects near each other emit light on each other. (Such as the bottom of the nose and the skin under the nose - they light each other.)

We want shader GC to correct the colors for display on the monitor, but this messes up the diffuse inter-reflection (IDL) calculation. Gamma corrected colors are not being presented as linear values but the lighting equation is based on linear values. The boosted values cause the lighting to be boosted, and this is undesirable.

The use of IDL without render GC is really troublesome. The whole point of IDL is to get accurate secondary lighting, but all lighting is inaccurate as it appears in the final image without gamma correction.

I could skip the shader GC altogether, but then it will look like crap unless you do a bunch of compensations - the kind we always did - like adding fill lights and setting shader response values to unrealistic levels. Doing that sort of thing is counterproductive when the intent is to use and benefit by a built-in accurate lighting and rendering model.

I could also build half-GC into the shader - where it does the incoming anti-GC, but does not do that final render GC. Then you'd have to do the final GC as a post-processing step on the whole image, outside of Poser. Or you could do it with my artistic lens. But all of these other tactics are ugly compared to just enabling IDL and GC, ala Poser Pro 2010.

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Renderosity forum reply notifications are wonky. If I read a follow-up in a thread, but I don't myself reply, then notifications no longer happen AT ALL on that thread. So if I seem to be ignoring a question, that's why. (Updated September 23, 2019)