Comments on: Object Materials – Some Rough Thoughts

By: Benjamin Supnik

Benjamin Supnik — Thu, 19 Mar 2009 08:02:00 +0000

Hi KRZ,

I should clarify something: we will _not_ be getting a material system like "brick" (e.g. small repeating textures that can be changed). We will not be getting multiple textures at all. Texture atlasing will _continue_ te be a requirement for making OBJs.

So I think that the issue of "do normal and bump maps belong together" is a little bit moot. You can't mix & match the textures because there aren't more than one texture to mix & match per object, so there is no loss of flexibility to combining a 3 channel normal map with a 1 channel gloss map. There is also not going to be independent UV map control for each texture.

By: krz

krz — Thu, 19 Mar 2009 06:33:00 +0000

ya i dont expect anything (i prefer to be surprised:), i just hope that the system you implement will be easy to extend. the way mentalray has to introduce new shaders with every release is horrible and i hope that other renders think about a futureproof implementation (by mimicking real world physical phenomena). e.g. mental ray had a shader with slots for specularity and reflectivity and surface roughness…but in reality all this three parameters are the same thing. (specularity is a fake, reflektion and reflection is controlled by the micro-roughness of the surface). i was just worried that you want to optimize the system too much (as you mentioned you maybe plan to bind the normalmap to a glossymap, and i think these two parameters dont have anything to to with each other)

By: Dave Duck

Dave Duck — Thu, 19 Mar 2009 00:19:00 +0000

Bump (by any method) would be a lovely touch.

By: Benjamin Supnik

Benjamin Supnik — Wed, 18 Mar 2009 19:26:00 +0000

krz – er, don’t get your hopes up. Seriously, those are good ideas, but it is unlikely that at least the first material classes will be significantly more complex computationally than what we have now. That would imply not being able to double the number of materials per triangle.

By: krz

krz — Wed, 18 Mar 2009 19:24:00 +0000

i would suggest a material system with parameters that come from physical renders as e.g. maxwell:

1. you can have multiple layers of materials
2. each material has texture slots for:
- color (great would be 2 color slots to achieve fresnel effects)
- roughness b/w: b=perfect mirror (maximum specular) w=lambert (no light bounces of, aka no specularity)
- transmittance/alpha: b=opaque, w=completely clear ,color adds tint
- bump: eighter a bumpmap b/w or a normalmap

multiple material layers should be able to be weighted. the result be normalized. that way you can do metals (only one material layer) and plastics (2 layers: first is a lambert that gives the color from colorslot e.g. red and the second layer is the coating that adds reflectivity (specular highlights in the color that is a result of colorslot of that layer and lightsource color, mixed by the roughnessvalue of this coating layer)