# Direction Create

- Type
- Projection
- Scope
- Position
- View

### reference

When reference is cell, the direction is crystallographic so direction indices are required and its parent must be a cell. When reference is atoms, the direction is described by two xyz coordinates so the direction becomes independent of the atoms used to define it.

    Example: <direction ... reference="cell"/> (default)
    Allowed values: cell, atoms (optional)

### u, v, w

Set the indices u, v, w defining a crystallographic direction. The three indices cannot be all zero. An error is shown when these indices are not indicated for a crystallographic direction or when they are indicated for an atomic direction.

    Example: <direction ... u="1" v="0" w="0"/> (no default)
    Allowed values: integer (required, coupled)

### vectors

Set the type of cell vectors, conventional or primitive, used to determine the direction with u, v, w indices. When the lattice is primitive there is no difference between conventional or primitive cell vectors. An error is shown when vectors is set for an atomic direction.

    Example: <direction ... vectors="conventional"/> (default)
    (defined in GAMGI_PHYS_DIRECTION_VECTORS)
    Allowed values: conventional, primitive (optional)

### model

An atomic direction is always represented as a line. A crystallographic direction can also be represented as a pole or a trace (for projected directions).

    Example: <direction ... model="line"/> (default)
    Allowed values: line, pole, trace (optional)

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