Glb.db -

If nothing lights up, your mesh is a perfectly solid, closed piece. : Go to File > Export > glTF 2.0 (.glb) .

If your GLB file has errors or isn't behaving like a single object, you can use specialized fix tools to automate the repair process: glb.db

Go to , select all vertices ( A ), and use Mesh > Clean Up > Merge by Distance to remove overlapping vertices. Check for "Solid" Integrity : If nothing lights up, your mesh is a