Open Paint 3D. An empty canvas will be visible.
Drag&Drop a 3D file onto the canvas. Stanford Bunny in .obj file format is used as an example.
Go to main menu and choose “Save as”/ “Speichern unter” to save the file.
Go to export file and choose GLB (which is a binary version of GLTF)
Drag & Drop into http://sandbox.babylonjs.com/ to test and view the model. The result should look similar to pic below.