A model’s unit cell is, at any given time, one of the following:
| Value | Description |
|---|---|
| none | The model has no unit cell (i.e. it is non-periodic) |
| cubic | The model's unit cell is cubic, with A=B=C and alpha=beta=gamma=90 |
| orthorhombic | The model's unit cell is an orthorhombus, with any cell lengths and alpha=beta=gamma=90 |
| parallelepiped | The model's unit cell is monoclinic or triclinic, with any cell lengths and angles |