element type code
1 = bilinear 4-node quadrilateral (can be degenerated to triangles)
2 = biquadratic 8-node serendipity (can be degenerated to triangles)
4 = linear 4-node tetrahedron
6 = trilinear "brick" hexahedron (can be degenerated to prisms or tetrahedra)
coming in a future version -- linear truss (bar) elements