HEX meshing is for 3-D SOLID geometry only, the result of the HEX Meshing command are 3-D Solid Hexaedral elements: a six-sided solid (brick) element with 8 to 20 grid points. This element is named CHEXA, and is the most commonly used solid element in the NX Nastran element library.
The CPENTA , CPYRAM, and CTETRA are also 3-D solid elements, but are used mainly for mesh transitions and in areas where the CHEXA element is excessively distorted. Solid elements are commonly used to model an isotropic continuum for structural and thermal analyses.
Best regards, Blas.
Blas Molero Hidalgo, Ingeniero Industrial, Director IBERISA • 48004 BILBAO (SPAIN) WEB: http://www.iberisa.com Blog Femap-NX Nastran: http://iberisa.wordpress.com/