Change here object and crystallographic data for a single direction or a list
of directions.
To modify a direction, click over its graphic image, or write its identification
(name and number) on the
Direction entry. To modify a list of directions,
press the button
List (after creating the list of directions with
Direction->Select). Parameters for empty entries or
Local choices
remain unchanged.
To change a direction name write the new name in the
Direction entry,
followed by the direction number (GAMGI needs the number to identify the direction).
To change the name for a list of directions, press
List first
and then write the new common name in the
Name entry.
Reference
GAMGI can handle crystallographic directions (selecting
Cell),
related with a cell containing the relevant crystallographic information,
and atomic directions (selecting
Atoms), defined by two non-coincident
atoms.
For a single direction,
Reference can be
Cell,
Atoms or
Local. For a list of directions,
Reference
must be
Local.
When
Cell or
Atoms is selected, the direction is recreated
from scratch (as if using
Direction->Create) and its old content is
removed. As this requires local information for each direction, it cannot
be done for a lists of directions. When
Local is selected, previous
features and contents are preserved, unless when specifically changed.
Cell
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).
Atoms
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.