How to fix non-manifold mesh in Blender

Certain mesh operations in Blender do not work on non-manifold meshes. In such a case, you may have to manually clean up or fix the mesh to remove the non-manifold elements and fill in correct elements.

1. First, learn what elements of a mesh cause it to be non-manifold.

2. Next, ask Blender to show you the non-manifold elements of the mesh. You may have to turn around and zoom into the mesh quite a bit to view such elements which are in obscure corners.

3. Finally, fix the shown non-manifold elements. To fix the mesh, you may have to display the normals in the mesh, remove elements of the mesh and fill in the holes correctly.

Your work is done when the display at the top shows zero non-manifold vertices, edges and faces!

Tried with: Blender 2.62 and Ubuntu 12.04 LTS