# Direction Create

- Type
- Line
- Projection
- View

Set here the properties of a crystallographic or atomic direction.

### Reference

GAMGI can handle crystallographic directions, related with a cell containing the relevant crystallographic information, and atomic directions, defined by two non-coincident atoms.

To create crystallographic directions, set Reference to Cell. GAMGI automatically shows a Cell entry, plus u, v, w entries to indicate the direction indices, plus a Vectors menu, to select the cell vectors to use, Conventional or Primitive. For the sake of simplicity, GAMGI does not accept 4-indice notation for planes or directions in hexagonal cells.

Pressing the mouse over a cell in the current layer, the cell identification is automatically written in the Cell entry. When a valid cell is found and its Type is Projection, the default Line page is automatically replaced by a Projection page.

By default, only one family of crystallographic directions is created. To create a set of families simultaneously, press the button Set (TODO).

When Reference is set to Atoms, GAMGI automatically shows two Atom entries. Pressing the mouse sucessively over two non-colinear atoms in the current layer, the two entries become occupied and the direction defined. After pressing Ok, an error is shown if the atoms are coincident.
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