Hi. I was struggling to get the Karma AOVs to work correctly, and then noticed that it worked correctly with CPU rendering but not XPU. When rendering with XPU the AOVs will be in the file, but when you view them in fusion or nuke it's just black. After reading the documentation further it looks like there is a special process for XPU aovs.

It says, "Shaders can export AOVs using a Mtlx Dot node with the note set to aov:name. For example, create a Dot node in your Material X shader netwrok with the note set to aov:foobar, then add foobar as the name of a Render Var in the render node, with the Source Type set to Raw."

Does anyone know how to do this? I add the Mtlx dot node but I'm not seeing a place to connect it with the Mtlx Standar Surface node. Also, for the note would I match the name of the aov in the Karma render node, for example aov:combinedglossyreflection

Any help appreciated, thx.

The mtlxdot nodes are inline exports. They export the connected input when the output is connected to the shader network. Free-floating dot nodes are ignored.

XPU has limited aov exports at present: LPE are not supported, e.g. Combined Glossy Reflection (C<RG>.*L).

Thanks for your reply. So the mtlxdot node doesn't actually have to be connected? Would you possibly have a hipfile showing the setup for this that I could use as a template? I'm a little new with AOVs so it's a bit confusing

FlurishArt
So the mtlxdot node doesn't actually have to be connected?

No, the mtlxdot node must be connected. It is similar in function to the RIS 'Tee' node from Renderman.

Ah I understand now. Ty this is very helpful!

Here is an example
Please remember you need to do an offline render for it to work (eg via the "karma" command line, or click "Render To Disk" on the Karma LOP

Cheers