CENTAUR has the capability of generating hexahedral elements. The hexahedral mesh generator starts by generating quadrilaterals (structured or unstructured) on the surface. These quadrilateral faces are then grown to create layers of hexahedra. The hexahedra match the surrounding prisms and tetrahedra utilizing pyramidal transitional elements, if necessary. Structured quad layers on the surface can also be generated resulting in high aspect ratio meshes that save large numbers of elements.