Why are faces being deleted when importing a mesh?

[Rinocore]

I created a raft in blender, imported the mesh to Roblox studio and it is missing some faces, they aren’t missing in blender even when I import the mesh back into blender.

[RegularRival]

If you want to fix the problem you might need to flip normals or you can use the solidify modifier for mesh

HOW TO FLIP NORMALS:

OR

HOW TO SOLIDIFY MESH:

[Rinocore]

I have tried both of these and it still deletes faces.

[70Night]

Have you checked its normals? This is how you do it:

Blue is good, Red is bad.

[Rinocore]

Alright I fixed it, there were duplicate meshes I found, I guess when I joined them I forgot to delete the mesh I started with.