Skin: Specmaps to roughness or reflection

[DrHemulen]

I'm a little confused as to what's the best option here?

A number for reflection and an inverted specmap for roughness?
A number for roughness and a specmap for reflection?

It seems that these produce similar results, but are there any definite pros and cons, or some other method altogether?

[sikotik13]

That's actually a really good question. I never use spec maps for anything, so I can only give more general observations. The reflection I use is a mix mat that includes the diffuse texture, and roughness depends on the lighting I'm using, and how "oily?" I want the skin to look. Roughness below .1-ish to me looks wet or oily, for a softer/dryer look, I'll usually bump roughness up to about .3-.6, depending on the lighting, again. I still use a slightly modified template from 3dmania in OcDS version 1.2, though, so if you're using a different version, my specific settings with examples would be virtually pointless, lol.

[Sorel]

I have actually been curious about this myself. Sometimes when I input a spec map I feel like the light doesn't look right on the figure. I dunno if that's because the material requires further tweaking, though I have messed around with the spec power and roughness.

[larsmidnatt]

i let the bump/normal/displacement break up the roughness of the skin personally. Occasionally I have used the provided specular maps and sometimes you can get results with them, but I have found there have been times when I actually didn't like the result of the spec map and ended up stop using them.

I reallly think most of the spec maps that come with Daz/Poser figures were designed around how Firefly/3Delight work.

I think if you have a non-human skin, then a specmap may be more useful than a human. Like a lizard would have more exaggerated shiny vs dull areas and a spec map may bring that out.

[DrHemulen]

Yeah I think you are right about that. Most specmaps looks like no thought went into them anyways, it's usually just the bumpmap with some kind of filter applied. I guess you could use some really low-res ones to indcate areas with more reflection (like lips) but no micro details.

[sikotik13]

I have noticed that overall I tend to lower specularity (by raising roughness) except in very specific instances. I'll leave roughness lower for lips/inner mouth, etc. which leaves said ares shinier, and suits my tastes, though I have no idea how realistic it may be. It pleases me, which at the end of the day is all that matters to me as a hobbyist trying to find my style.

And I agree, I'm pretty sure the spec maps are generally intended to function as a cheat for the firefly/direct3d render engines, not so much for more correct lighting solutions (they usually look borderline awful with Luxrender as well).