Patch dependent meshing uses the same mesh generation method utilized in ANSYS TGrid. A tetra mesh is generated, starting from the outer geometry. Patch dependent meshing is especially effective in cases when the geometry is complicated and accurate mesh generation is needed. However, the mesh may also be finer in areas that are not important in your calculations. Patch independent meshing uses the same mesh generation method utilized in ANSYS ICEMCFD. A tetra mesh is generated, starting from the inside of the mesh generation region. The advantage of patch independent generation is the ability to ignore points within the model that have no relation to your calculation. It is also an effective method to use when working with CAD models of poor quality, possibly saving significant time in mesh generation. However, there is a risk in creating a mesh that does not maintain high fidelity of the geometry.