By setting the same namespace on different stand-ins, their nodes will be able to "connect" with each other. This will allow exporting shapes and shaders separately. The parameter "Force Shader Assignments" (that is necessary for this workflow) appears in the export options UI and only appears when "Export Shaders" is disabled.
To export standins and shaders separately, the workflow would be :
- Export your asset with only "Shapes" enabled with "Force Shader Assignment" enabled.
- Export your asset again with only "Shaders".
- Create two standins and load each of them.
- Set the same Namespace string for both standins.