The Nastran file type supports both Nastran and Nastran-L grid export. The regular format (Nastran) reads 8 characters for real values whereas the large format (Nastran-L) reads 16 characters. Both formats are based on the commercial software product of the same name (Ref. 17).
The export of domains, blocks, and block faces is supported. Structured grid entities are exported as unstructured. Only CQUAD4, CTRIA3, CHEXA, CTETRA, CPENTA (prism), and CPYRAM (pyramid) elements are supported.