Change here the properties of a crystallographic or atomic direction 
(or list of directions, previously selected with Direction->Select, 
when 
Global is pressed).
Parameters for empty entries or 
Local choices remain unchanged.
To change the direction name write the new name in the Direction entry, followed
by the direction number (GAMGI only needs the number to identify the 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.