Before generating the mesh, you should confirm that the geometry is free of any flaws that would inhibit optimal mesh creation. The Tetra mesher requires that the model contains a closed volume; if there are any holes in the geometry that are larger than the local tetras, the mesh may not be computed. The Build Topology operation is used to check your geometry and represent connectivity between adjacent surfaces with different colored curves. You can correct any identified problem on the mesh or you can repair the geometry in that vicinity and repeat the meshing process. For further information on the process of interactively closing holes, see the following sections.
Note: If you want to save the changes in the native CAD files, perform any geometry repairs in a direct CAD interface.