Add A Base Mesh In Houdini For Static Mesh Assemblies

Hello, I’m trying to add a base mesh to a Nanite Static Mesh Assembly in Houdini using the Nanite Schemes.

Here is an example from the tutorial files provided here: Nanite Assemblies in USD: Part 2 - Houdini Tutorials | Tutorial

I’ve tried a bunch of things to adjust the scheme, but the Torus in this example is always imported as an instance of the Static Mesh Assembly:

I’ve looked through the properties provided with the Nanite API scheme, and I do not see any options to apply a base mesh to a static mesh assembly:

I know this is possible, as if you are making an asset with Unreal’s Procedural Vegetation tool, you can choose to export this as a static mesh:

When that tree is exported, the trunk is integrated as the base mesh and does not show up in the list for the assembly:

I know how to do this with skeletal meshes, with the unreal:naniteAssembly:skeleton prim path, but I cannot find an option for static meshes.

Let me know if you need any more information, or if you want me to share any files.

Thank you!