Bifrost assign_material not working

[lennart.oberscheidt]

Hi everyone, just a quick question:

Does Arnold 6 / Bifrost 2.0.4.0 Maya 2018.6 not support assigning materials to geometry in the bifrost graph? Just a few instanced cones. Viewport displays the assigned aiStandardSurface (red diffuse color) just fine on the instances. Anrold renders the cones with the standard lambert or whichever material is assigned to the Mesh Output of the Graph within Maya.

Do i miss something her?. Since Bifrost is so *ahem* well documented i assume this is the correct way to go about assigning shader from within the graph but i might be wrong.

Cheers,

Lennart

[lee_griggs]

That should work. Also, try assigning the shader in the Hypershade window to the bif shape in the outliner.

[lennart.oberscheidt]

Well it unfortunately doesn't… that way anyway. Found a workaround though: While troubleshooting with multiple instances I never got it to work and arnold rendered the instances with the default material. Assigning the material to the bif shape of course defeats the purpose of assigning materials per instance in the graph (althought that works if all you need is one material on all the instances).

Graph that doesn't work:

I then wanted to try assign materials from within the graph post-instancing to see if at least that works and to my surprise: Just dropping an assign_materials node after the set_instance_geometry (without actually assigning any mats with it) does the trick! However, I strongly assume that isn't the intended behavior and seems to not be documented anywhere. You (or the bifrost Team) might want to look into that 😉

Cheers,

Lennart

Sample files here:

Bifrost_Material_assignment_working.mb.zip

Bifrost_Material_assignment_notworking.mb.zip

[Stephen.Blair]

What's happening is that the Lambert shader is assigned to the instances, and that overrides the shaders you applied to the source objects.

When you added in that assign_material after set_instance_geometry, that cleared the instance shader assignment (no shader was assigned to the instance). So then the shader assigned to the source object was used.

I think we should not assign any shader to the instances. Then by default, the shaders assigned to the source objects will be used. IIRC, that's how instancing works elsewhere in MtoA.

Thanks for reporting the issue.

[Anonymous]

@Lee Griggs

i don't see the big shapes in outliner. Is there any trick to make them appear?

[Anonymous]

how can i make the bifShapes visible in outliner?

[Stephen.Blair]

Click Display > Shapes

[Anonymous]

looks like something has changed with Maya 2020.4. On 2020.3 it's working that way. With 2020.4 i can't find a way.. wich makes assigning shaders a Lott less intuitive

[Stephen.Blair]

I see a bifrostGraphShape in the Outliner

[Anonymous]

well yes, me too ... but can't select single meshes and assign a shader, like the guy does here
https://youtu.be/uSA_RNl9g9o?t=900

Looks like i have to do do that in the bifrost-graph-editor now