Working Outside of Arnold Shader Network

[jamesearnest244]

I have a Standard Surface node available in the /mat context, outside of an Arnold Shader Network, but I can't get a render if I use it. I understand this is a deprecated workflow, but I'm wondering if there's still a way to work like this. The reason is that I want to use other external nodes from Houdini as part of the shader network, which aren't available inside of an Arnold Shader Network. Does anyone know of a way I can pull this off? Alternatively, maybe there's some hack to access these nodes inside the network?

[Stephen.Blair]

Do these external nodes from Houdini actually do anything in the render?

[jamesearnest244]

Yes. For example, some procedural noise and patterns that I'd like to use in the shader. They're just simple nodes that output RGB values, so I don't see why they'd be incompatible with Arnold. Apparently they used to be, when working directly inside the /mat context. But they don't appear in the Tab menu inside an Arnold Shader Network.

[Stephen.Blair]

Can you put these RGB values as user data (attributes) on the geometry?
Then you can use Arnold user data shaders.

[jamesearnest244]

I can't, because these nodes are only available in the /mat context. No way that I know of to reference data from /mat in /obj, to get it on the geometry itself. So... no hope?

[julian.hodgson]

We only supporting Arnold shaders, and the /mat context contains shaders from all renderers. So you should work inside the arnold_materialbuilder and so only use the VOP nodes that you can find in the there which we can translate.