USM3D is an all tetrahedral, cell-centered, finite-volume solver from NASA Langley Research Center. For more information, visit the official web site at: https://tetruss.larc.nasa.gov/usm3d/overview/.
Grids are exported in the USM3D format in Unformatted and in Double precision. An additional CAE attribute can be specified to control maximum exported segment size and thus convert export automatically to multi-segment. See the USM3D page under Set Solver Attributes for more details.