Shiny diffuse material

[surena]

Hi all,

Well, in order to normalize shaders, I write a little resume of comparison of yafaray's shiny diffuse material with others:

Cycles:
Diffuse only shader has roughness component, like on yafaray oren-nayar sigma. (I propose to disable lambert model, but this should be discussed). Also color input.
Has a glossy shader that can be used with roughness 0 to make a mirror.
You control mirror weight blending shaders.
Emission is a different shader that must be mixed.

Mitsuba:
Similar as Cycles' diffuse shader. Also with color input.
Mirror is controlled with a conductor shader, more complex than cycles one.
Blending with blend shader.
The emission goes with the material, not with the shader.

Luxrender:
http://www.luxrender.net/wiki/LuxRender_Materials_Matte
Diffuse shader is named matte. Also with sigma and color.
In this case there is a mirror only shader, with custom IOR and presets, also thickness.
Has emission as property on the material.
Translucency goes with another material:
http://www.luxrender.net/wiki/LuxRender_Materials_MatteTranslucent
http://www.luxrender.net/wiki/LuxRender_Materials_GlossyTranslucent

Thea render:
This is a different approach, it works with weighted layers.
As said on the manual:

Basic material is a model that consists of a diffuse, translucent and a Fresnel based specular component.

Is more similar to yafaray one.
All thea materials have emission as option, is a material property, not from the layer.

Vray:
Vray base material is named VRayMtl, is a sort of all-in-one material, with reflection, refraction and translucency.
https://www.vray.com/vray_for_3ds_max/manual/vraymtl_parameters.shtml
Almost every option can be mapped (square on the side of the control).
Does not have emission, it's from another material (VRayLightMtl), so should be mixed or be alone.

Octane:
https://docs.otoy.com/#51Diffuse%20Materials
Controlled also with roughness to simulate oren-nayar.
Opacity is also mapped.
It has an emission and transmission value inside the shader.

Lightwave:
Lightwave had an all-in-one shader editor, with no different shaders; since some versions ago, it has the node editor, with more shaders in addition. Now they're about to change to PBR materials, and I don't know which model will be used.

All of them have also bump/normal, which I don't mention.

As I can see we have to consider from which model we want to inspire.

Personally if we don't have shader nodes I prefer an ubershader with options like vray's one, also can be convenient to vray users than wants to test yafaray. And if needed create specialised shaders that can be mixed with blend.

If we're going to move to nodes, the cycles approach seems good to me.

Finally, I think oren-nayar should be the default model, with default sigma value of 0.
Important, to have a selector of default sigma values:

Felt: 0.414686
Rough plastic: 0.278057
Leather: 0.179776
Velvet: 0.751002
Pebbles: 0.443289
Plaster_b: 0.543788
Rough paper: 0.311376
Roof shingle: 0.819147
Rug_b: 0.613889
Sponge: 0.872413
Wool: 0.978133
Quarry tile: 0.360574
Slate_b: 0.309590
Human skin: 0.579386
Brick_b: 0.275990
Linen: 0.514593
Cotton: 0.482679
Stones: 1.107168
Concrete_b: 0.308956
Concrete_c: 0.461930
Wood_b: 0.351271
Tree bark: 0.293226

What do you think?

[David Bluecame]

Thanks for your very detailed information. I will take all that into consideration for sure.

I have a question: in those systems, when you use a texture for mapping a value (for example transparency or color), are those renderers using *only* the value from the texture (ignoring the base value when using textures) or are they doing (as YafaRay does) a combination of the base value for that property * texture value?

Thanks.

[surena]

Well in case of cycles, when you assign a texture, to a diffuse node, it takes directly the value.
If you want to multiply you must add a multiply node to the color output.

Cycles

Screenshot - 15_03_2016 , 10_02_21.jpg (21.46 KiB) Viewed 3408 times

In case of luxrender, you have the two flavours:
-Luxrender classic, with the multiply possibility if you activate it (not nodes):

luxrender classic

Screenshot - 15_03_2016 , 10_05_24.jpg (30.64 KiB) Viewed 3408 times

You also have nodes on luxrender classic, they're like luxrender core ones.

-Luxrender core:
Same as cycles, you can add a multiply node between texture and material.

Luxcore

-Vray for blender
It work with nodes, it seems the same as the others that work with nodes.

Vray_blender

-Vray for max
On max if you don't use nodes, you have mix value with every map from 0 to 100. It will mix the texture with the base value of the material, like yafaray then.
http://www.impossible3ds.com/en/vray-material-maps-rollout/

-Octane
Seems similar as blender cycles' one:
http://blenderartists.org/forum/showthread.php?363265-How-do-you-map-and-render-images-in-Blender-Octane-Render

Thanks!