Blending Material Group

[gryphiz]

Hello
how can i blend two group materials together in modo?

[Robert]

The Modo way is to define two shader groups. So the one shader node per group

[vladimir.nedev]

You have three options for doing this:

1. Use a texture set to the "Group Mask" effect. This essentially blends all material properties using the texture as a mask, and then computes the shading/lighting only once.
This means you can blend only materials of the same type (only MODO material, only V-Ray material, only V-Ray alSurface material, etc.).
This should be the faster option as well (since lighting is computed only once), but it doesn't allow multiple specular lobes like options 2 and 3 below.
Also, only the texturable material properties are blended in V-Ray (diffuse color, amount, specular color),
the non-texturable are not blended, but instead taken from the top-most material ("use fresnel" state, "use refractive index" state, etc), which can lead to problems.



2. Use multiple Shader items like suggested by Robert. The Shader item tells MODO(and V-Ray) that shading/lighting needs to be computed with the material properties as specified up-to the Shader item.
In this case, you use the texture from option 1., as a layer mask on the Shader item itself. You also need to move the materials above the Base Shader, as otherwise its shading result will overwrite their shading result.
This option is slower than 1 , since lighting is computed multiple times. It is equivalent to the V-Ray Blend Material.



3. Use a V-Ray blend material, with the mask texture set to the "vblend Amount *" effect.
This option is not very convenient at the moment as you can select only material items (but not material groups) in the V-Ray blend material, which means you have to manually connect the material's textures in the Schematic.
Otherwise this is similar to option 2 in that lighting is computed multiple times and you can have multiple specular lobes and generally more complex materials.
Eventually I will add the option to connect materials groups to the V-Ray blend material, so the textures inside can be used.
This will hopefully make option 3. the most straightforward and powerful.
This setup won't work in MODO's render unlike options 1. and 2.



Attaching some example scenes. The textures are from MODO's standard content.

Greetings,
Vladimir Nedev

[1funk]

Eventually I will add the option to connect materials groups to the V-Ray blend material, so the textures inside can be used.

Looking forward to seeing this. It will make things a lot nicer I always hated having to move groups with additional shaders to the top of the shader tree

[GidPDX]

Nice to know we can mask shaders in MODO- never thought to even try!

Which of these are supported in GPU RT? Are all of them?

For using a group mask, it seems to only work in GPU RT if you are using the MODO material, but not the Vray material or ALshader.

I'm fairly certain the Vray blend material works though in GPU RT too.

[Robert]

Would be useful here to have shader group support as input for the vray blend material

[1funk]

Eventually I will add the option to connect materials groups to the V-Ray blend material, so the textures inside can be used.

We were talking about this on skype today, so I thought I'd bump the thread. Are you still planning on adding this option?

[vladimir.nedev]

We were talking about this on skype today, so I thought I'd bump the thread. Are you still planning on adding this option?

Yes, I have it logged as an issue, but it will probably have to wait quite a bit since it's complicated and there is other stuff to do as well.

Greetings,
Vladimir Nedev