Principled vs diffuse/glossy

[joepal]

So I downloaded a blender test build and played around with the new principled shader. Kind of nifty. Very useful. The significant objective gain you can get over most other prior node setups, is that it does away with the very annoying fresnel artifacts you get when the camera ray angle approaches 90 degrees vs a surface normal (this is especially visible when using normal maps).

But outside that, it very conveniently merges pretty much everything one would want into one node.

Here's a test render with principled skin (left) vs classic diffuse/glossy/fresnel (right). It's not entirely fair since I also enabled some sss in the principled:

Node setup for principled:

Node setup for old-style:

[Aranuvir]

Interesting, I recently watched a video by Andrew Price about it. I haven't tried the new Blender builds yet and I was missing some observations on building "principled organic material" in the video. Can you say somethings about rendering speed, especially when it comes to SSS? (though, remembering your system specs, I guess, your render times are somewhere in nano seconds anyway )

[joepal]

I didn't measure, but I experience it as faster overall. Which is also what I hear from other people trying it: it's supposedly a pretty optimized solution that is faster than when building something corresponding by combining other nodes.

[blindsaypatten]

One video I looked at said the Principled Shader takes Roughness maps rather than Specular maps, although I notice it does have a Specular input. MakeHuman supports Specular maps but not Roughness maps. Are there plans for adding Roughness (or glossy) map support to MakeHuman? Would that be a reasonable feature request?

[joepal]

For supporting it as a hint for exports possibly, for implementing it in OpenGL so that it can be shown inside MH I don't know. It'd also involve updating MHX2 though, which is outside what the MH dev team as such does.

[blindsaypatten]

For supporting it as a hint for exports possibly, for implementing it in OpenGL so that it can be shown inside MH I don't know. It'd also involve updating MHX2 though, which is outside what the MH dev team as such does.

I think it would be good to have the ability to set a roughness map on the material even if it isn't reflected in MH, the idea being that the assets have all the data needed if the external environment can make use of it. I volunteer to produce a patch for/version of MHX2 able to make use of it.

[joepal]

http://bugtracker.makehumancommunity.org/issues/1183

[blindsaypatten]

From the issue tracker:

A lot has happened since the specification of the current MHMAT format. Even if we don't reflect certain properties visually inside MH, it'd be beneficial to be able to represent some extra material properties for exports.

Examples would include roughness map, tangent map, clearcoat normal map, sheen, ior...

Note that for specific shaders, in specific situations, we have support for arbitrary properties (floats, vectors or textures). So if it is something specific, then those can already be used, without adding to the mhmat format.

To make sure that I've got the terminology straight, in the case of making use of the Principled Shader, does it make sense to define a shader of the type described in the MH docs (litsphere, phong, etc.) or, since things like IOR and roughness maps are physical properties should they be added as properties at the same level as transparency and normal maps, or both? I haven't gone through all the Principled Shader inputs to see if any of them are "shader specific".

[Mindfront]

I really longing for the release of 2.79 even though i must adapt my skin material once again. Finally a one size fits almost all shader which will do Blender Cycles much more user-friendly. I'm tired of the node spider web. And with the shadow catcher it will be much easier to use HDRi as the only environment, as I never got the render layer shadows to work satisfying.