The 
Surface Connectivity Diagnostic tool is used to identify free or non-manifold surface edges in the model. These defects are analogous to those that occur with meshed models, however, it is advantageous to correct these problems in the geometry model before meshing. If connectivity defects exist, they can be corrected using the Surface Repair Tools in the Modeling menu.
To access this tool, import a geometry file, e.g. IGES (*.igs), STEP (*.stp, *.step), or Parasolid (*.x_t, *.x_b, etc.) using
> Import, and then select ().
Dialog elements
- Find free edges
- Select this option if you want the diagnostic to search for surface edges that are not shared by other surfaces. In a correctly connected geometry model, each surface edge should be shared between two surfaces.
- Find non-manifold edges
- Select this option if you want the diagnostic to search for surface edges that are shared by more than two surfaces. In a correctly connected geometry model, each surface edge should be shared between two surfaces.