# Cell Modify

Change here position and orientation for a single cell or a list of cells.

To modify an cell, click over its graphic image, or write its identification (name and number) on the Cell entry. To modify a list of cells, press the button List (after creating the list of cells with Cell->Select). Parameters for empty entries or Local choices remain unchanged.

To change an cell name write the new name in the Cell entry, followed by the cell number (GAMGI needs the number to identify the cell). To change the name for a list of cells, press List first and then write the new common name in the Name entry.

### Translation

The origin of a cell object, defined by its (0 0 0) node, can be changed using the X, Y, Z entries.

By default, in Conventional, Primitive and Parallelepiped volumes, this node is at a corner of the cell volume, in a Sphere volume it is at the center, and in a Wigner volume it is at the center of the first Wigner-Seitz cell.

To define exactly the cell translation, relatively to other cell or relatively to the current layer, press Align.

### Rotation

The orientation of a cell object, defined by the Euler angles theta, phi, psi, can be changed using the E1, E2, E3 entries.

Euler angles in GAMGI are defined as follows: first, the (x, y, z) referential is rotated theta degrees (between 0 and 180) around the y axis, then the referential is rotated phi degrees (between 0 and 360) around the initial z axis, and finally it is rotated psi degrees (between 0 and 360) around the new z axis, always in the direct, counter-clockwise, direction. If the first Euler angle (theta) is zero, the old and new z axis coincide, thus (0, 0, 10) and (0, 5, 5) represent the same rotation.

By default, the first conventional vector is aligned with the x axis (even if conventional vectors are not actually represented), the second vector is in the xy plane and the third vector has a positive z coordinate (pointing to the user), corresponding to Euler angles (0, 0, 0).

The cell orientation is independent of the volume representation. This way, conventional, primitive and Wigner-Seitz cells can be easily compared, as they have the same orientation.

To define exactly the cell rotation, relatively to other cell or relatively to the current layer, press Align.