In order to be able to create a volume mesh, it is necessary that selected surface meshes provide a watertight domain (or several domains), meaning that it is closed and does not contain any holes (so that the model has clear separation between the interior and exterior).
GHeal is a Griddle utility that can be used to identify certain surface mesh problems and fix them. In automatic mode, GHeal helps with such issues as:
- patch mesh holes,
- patch (mend) cracks (elongated fissures on the external boundary of a surface mesh),
- clean clashing faces,
- remove small protrusions (a small number of mesh faces attached to the main mesh in non-conformal way),
- split non-planar quadrilateral faces,
- align mesh normals, and
- clean (cull) redundant nodes and detached faces.
These functions may be run altogether or individually, which in certain cases may be preferable. In general, GHeal functions often identify and clean mesh problems more efficiently than user efforts to fix a mesh manually or by using the built-in Rhino mesh repair tools. Detailed, custom manual mesh editing using Rhino mesh repair tools are always available (e.g., patching a single hole where the user must select the boundary of the hole).