Hi,

I have some custom shader elements I'd like to export in a materialx shader.
As much I as could find out the only way to write custom aovs from a mtlx shading network is to create a mtlx dot node and write my aov name into the notes input, e.g. aov:my_great_aov and create the appropriate renderVar.
Can anyone approve this, or did I miss another way to do it?

Is this for Karma? Does it need to be a mtlx material and not a karma material?
When using a karma material the karma aov node can be used.
MaterialX doesn't natively support AOVs which is why the dot workaround is needed.

We usually do it this way if you don't care about using a Karma_AOV node.

Unfortunately we export our shading networks from Maya as materialx so we do not have access to the karma aov node.
But it looks as if only a shading connection is needed in the surface shader e.g.:

color3f inputs:aov:mtlxAOV.connect = </materials/mtlxmaterial/mtlxcheckerboard1.outputs:out>

If I insert this line in my shader I was able to write the mtlx outputs. So I can manipulate the material USD file after export and add this connection to my exported surface shaders and it could work.