OVERFLOW export supports 3D structured grids only. Pointwise writes only
OVERFLOW's BCINP namelist.
Note that while Pointwise can create overlapping grids as required for
OVERFLOW, the hole cutting and other overlap calculations must be computed
using some other software such as PEGSUS, OVERFLOW's preprocessor. In fact,
the grid exported for OVERFLOW is actually formatted for PEGSUS. The PEGSUS
grid file is Fortran unformatted, and you are given a choice of Single
or Double precision. This grid file also contains the block names.