# Direction Create

- Type
- Projection
- Scope
- View

### autonomy

When autonomy is none, rotating, moving, scaling the direction corresponds to rotating, moving, scaling the parent object. For crystallographic directions, the parent object is the cell containing the relevant crystallographic information. Atoms in the thickness region are linked to atomic directions.

When autonomy is all or partial, the crystallographic or atomic direction can be rotated, moved, scaled, independently of its parent. When autonomy is partial, atoms in the thickness region were linked to the atomic or crystallographic direction. When autonomy is all, atoms in the thickness region were copied to the atomic or crystallographic direction.

    Example: <direction ... autonomy="none"/> (default)
    Allowed values: all, partial, none (optional)

### thickness

The polygonal representation of the direction is expanded as much as possible, limited by the cell volume, in crystallographic directions, and by the atoms within the thickness range of the direction defined by the first two atoms, in atomic directions.

    Example: <direction ... thickness="0.0100"/> (default)
    (defined in GAMGI_CHEM_DIRECTION_THICKNESS)
    Allowed values: positive real (optional)

### o1, o2, o3

A direction can be defined indicating explicitly the coordinates of a node where the direction passes. For each direction family, there is a direction passing through the origin node and as nodes are equivalent, it follows that for any node, there is a direction of any family passing through there.

When the lattice is primitive or vectors are primitive, coordinates o1, o2, o3 are enough to identify any cell node. By default, a crystallographic direction passes through the origin, with node coordinates equal to 0, 0, 0, respectively.

    Example: <direction ... o1="0" o2="0" o3="0"/> (default)
    Allowed values: integer (optional, coupled)

### o4

When the lattice is centered and vectors are conventional, the coordinates o1, o2, o3 indicate the node in the lower-left corner of the cell where the direction passes. A fourth coordinate o4 is needed to point the centered node where the direction passes. By default, o4 is 000, so no change is introduced. When the cell lattice is primitive P or the vectors defining the node are primitive, that is the only possible value for o4. For I, C, F, R centered lattices, o4 can also take the values:

    I: 111
    C: 110
    F: 110, 101, 011
    R: 211, 122

corresponding to the numerators of the inner node coordinates, (1/2 1/2 1/2) for I lattices, (1/2 1/2 0) for C lattices, (0 1/2 1/2) (1/2 0 1/2) (1/2 1/2 0) for F lattices and (1/3 2/3 2/3) (2/3 1/3 1/3) for R lattices.

    Example: <direction ... o4="000"/> (default)
    Allowed values: 000, 111, 110 101, 011, 211, 122 (optional)

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