i was trying to build a group of USD assets from a old usd assets(using the geo/uv and create materialX to replace the old invalid MDL materials from Omniverse)
I use a SopCreate node to get the geo. inside the node. just some regular process on meshes.

here is the lop net work to compose the usd assets


basically i create a materialX primitive and assign to the geo primitive. for both geo and material i setup the layer path. and finally use a usd-rop to render top level usd file(Aligned.usd)

everything works fine until i tried to work with Tops.


in the Top network, first i use a file pattern to get all old usd file that i need. then i do some attribute create and delete. after everything prepared. i use a ROP USD OUTPUT node to render the usd assets.


here is the error i got


I might have some misunderstand with the ROP USD OUTPUT node.or is it something i setup wrong?