As part of the integration with Substance, you can import SBSAR files to use as materials in VStitcher. You add such a file in the same way as you would normally add a material file.
For example, to import such a file as a fabric:
If the Materials tab is not already open, on the Resources tabs, click Materials.
If not already open, click the Garment tab.
Go to the Fabrics section and click . A menu is displayed.
Click Add Fabric. A file explorer window is displayed.
Navigate to the file you want to add then select it.
Follow any on-screen prompts as required.