[EMSUSD-2138] correct way to use exportMaterialCollections

^{Originally posted by **willDTF** November 29, 2024}
I need to export USD from maya with material collection assigned to objects

reading usd-maya [documentation](https://github.com/Autodesk/maya-usd/blob/dev/lib/mayaUsd/commands/Readme.md#command-flags-1), I need exportMaterialCollections and according to this [ticket resolved](https://github.com/Autodesk/maya-usd/pull/2442), i dont need to setup materialCollectionsPath argument. so i tried :

`cmds.mayaUSDExport( exportMaterialCollections=True, file=usdFilePath, )`

this doesn't work, no collection are created. then :

`cmds.mayaUSDExport( materialCollectionsPath='/Mtl', exportMaterialCollections=True, file=usdFilePath, )`

same result. i tried many variations, without success. The only step forward i've made is with :

`cmds.mayaUSDExport( exportCollectionBasedBindings=True, exportMaterialCollections=True, file=usdFilePath, ) `
material collections is created with the addition of exportCollectionBasedBindings, but no objects are in the collections

`cmds.mayaUSDExport( exportCollectionBasedBindings=True, exportMaterialCollections=True, file=usdFilePath,materialCollectionsPath='/Mtl' )`
gives the same result that the previous, collections exist but empty

How can I properly export a USD file with material collections assigned ?

thank you