These elements are available via the ET family of commands only and are inaccessible from within the GUI:
| REINF263 | 2-D Smeared Reinforcing |
| REINF264 | 3-D Discrete Reinforcing |
| REINF265 | 3-D Smeared Reinforcing |
| SURF251 | 2-D Radiosity Surface |
| SURF252 | 3-D Radiosity Surface |
| INFIN257 | Structural Infinite Solid (generated via the EINFIN command) |