templargfx opened this issue on Apr 15, 2014 · 67 posts
bagginsbill posted Wed, 16 April 2014 at 7:00 AM
It's very hard to share specular setups involving maps - nobody (and I mean no two vendors) can seem to agree on the interpretation. Thus, we have to futz with levels after applying every texture set involving a specular map.
Then you have the additional complication of forgetting to set gamma = 1 (or forgetting to mention to others that you did) on the specular map.
If you're using the red channel setup (as many do from copying my S+B shader or using EZSkin) you also have to accept that this is gamma = 2.2 data, and will be altogether different intensity as well.
What you have to learn is not a certain level - pay no attention to tg's particular values. Rather, you must understand what the level multiplication looks like when too high or too low and be ready to adjust. You can't treat the shader as a black box with simple inputs you drop in from random vendors.
The thing you really want to discuss is
What is the correct roughness for the specular node you've chosen (ks_microfacet). Is that node going to behave under the conditions you intend to light the model? (Hint: If you're doing a no-lights render as I frequently do now, the ks_microfacet does NOTHING.)
Does the real material (in this case, skin) exhibit dual roughness as do pearls and require two nodes?
Does the real material exhibit colored specular reflections (as do metals)? If you think skin does, then you would use the colored input on the specular. Otherwise, it would be white.
The thing I'd most point out during the experiments is this: It is very common to add a string of nodes and think you've improved things, when they're actually doing almost nothing. I have seen many complicated shader trees that plug into black. Much discussion around the purpose and results of such a shader tree made me laugh as it was doing nothing at all.
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)