Bad Mesh for STL File Help

Can anyone help me repair this mesh in order to make it a good mesh for 3d printing? Need a good STL file to send to the printers.
Final_Model_Observatory_3D_PRINT.3dm (1.5 MB)

Hi -
There is one mesh (one of the 2 “Icosphere” objects) in that file that gets flagged as a “bad mesh” - there is one face in that mesh that has flipped normals. That can be fixed with the UnifiyMeshNormals command.

The biggest issue in this model is with the open meshes. Use SelOpenMesh to select these. You can easily duplicate the planar borders of the 3 ring-shaped open meshes with the DupBorder command, create planar surfaces from those, and extract the render mesh. Finally join those caps with the open rings.

That leaves the two meshes named “Icosphere”. I don’t know what your plans are for that one. The easy way out is to join those two into one mesh, and then use FillMeshHole to close it.