Feature Request: Optional Export of Bone Xform Hierarchy in USD Export

[SttevanCJoga]

Optional Export of Bone Xform Hierarchy in USD Export

Summary

In the current USD export workflow from 3ds Max, bones are exported as a hierarchy of Xform prims. While this structure may be useful in some contexts, it introduces unnecessary data in downstream exports—particularly in chaser exports—where these Xform prims are not needed.

Problem

The automatic inclusion of bone Xform hierarchies in the USD export results in cluttered scene graphs and complicates post-processing, forcing to change the name of the root prim bone at the export in the options and loses the "reference" from the actual import and export.

Proposed Solution

Introduce an export option that allows users to choose whether bone Xform hierarchies should be included in the USD export. This would give users finer control over the output and streamline workflows that do not require these prims.

#usda 1.0

def SkelRoot "Model"
{
    def Xform "Skel"         # < --- Start
    {
        def Xform "Shoulder"
        {
            def Mesh "Shoulder_Bone"
            { ... }
            
            def Xform "Elbow"
            {
                def Mesh "Elbow_Bone"
                { ... }
                
                def Xform "Hand"
                {
                    def Mesh "Hand"
                    { ...  }
                }
            }
        }
    }                        # < --- Ends
    
    def Mesh "Arm"
    { ... }
    
    def Skeleton "Bones"
    { ... }
}

[wallworm]

Great idea. Noted for a possible future improvement.

[barbalt]

Hello @SttevanCJoga ,
This has been addressed in our latest release (v0.13.0).

The Export ui now has a new option to Preserve Bone Meshes which can be disabled to remove the current default behavior.
Of course, the option is also available on script:

local exportOptions = createDefaultOptions()
exportOptions.PreserveBoneMeshes = false
USDExporter.ExportFile exportPath exportOptions:exportOptions