This is my model. I'm trying to create a skyscraper
Now in edit mode is this one:
As you can see the many polygons creating my model are also into the skyscraper, i.e. they don't finish on the surface of my model but they continue inside it. This is because i create many polygons that i combine each other to create a bigger model. In the end i simply unified all meshes in one with CTRL + J. Then inside my model there are vertices, faces and edges.
The problem is this one: i have tried to export my model in fbx and this is the result:
Why I can't export in fbx my model?
EDIT FILE BLEND