Link cells to other objects, for example to build crystals and glasses.
Hierarchy
Cells can be linked to objects above or below, in the Gamgi hierarchy.
Pressing the button
Below (the default), the
Objects menu
shows the classes of objects that can be owned by cells: Cluster, Molecule,
Group, Plane, Direction, Atom, Orbital and Text. Pressing the button
Above, the same menu shows the classes of objects that can own
cells: Layer and Assembly. When the chosen
Hierarchy is
Above,
the link methods designed to add multiple objects to cells are disabled:
Independent,
Automatic and
Random.
Object
Gamgi expects users to identify first the cell or list of cells
and then the object to link. When the
Cell entry is active
and empty, clicking the mouse over a cell, on the current layer
(local selection), its identification is transported to the
Cell
entry. Gamgi is now expecting users to click on a object of the class
currently selected in the
Object menu. This object can be in
a different layer or even in a different window (global selection).
To select a visible object in a different layer, in the same window,
just press the mouse over the object, as if it was in the current
layer. To select objects without visual representation, as layers
and lights, press the mouse over the graphic area in the window,
to create a menu with all the objects of that class in the window,
which can then be selected. To select an object in a different
window, with the mouse, use exactly the same procedure, in that
window.
Method
Gamgi suppports three linking modes for cell objects:
Object,
Crystallographic and
Random.
The
Object method (the default), links a cell to a single
Object. When the
Hierarchy is
Above, the cell
is unlinked from its current parent and linked to the object. When
the cell is moved to a different layer, all its bonds to other
objects are autmatically removed. When the
Hierarchy is
Below, the object is unlinked from its current parent and
linked to the cell. An error is issued when the parent already
owned the child object.
After the linking operation, Gamgi always puts on top
the window and layer containing the linked objects.
The
Crystallographic method is used to link the selected
Object to the various cell nodes, in order to build crystals,
liquids and other nanostructures.
The linked objects can be handled independently of the cell:
they can be rotated, scaled, moved, removed, copied, as if the
cell did not exist, for example to create defect crystals. Users
can specificy patterns of occupation for the cell nodes, for example
to create mixtures of different liquids, or to build multi-layer
arbitrary nanostructures.
The
Random method is an implementation of the Jodrey algorithm
to build a Random Close Packing (RCP) structure: the cell volume is
randomly packed with atoms copied from the template atom selected as
Object.
The RCP structure has the highest volume density among
amorphous structures (0.62 - 0.64), which compares with the highest volume
density among crystalline structures (0.74). The RCP structure is particularly
suitable to describe metallic glasses, due to the nondirectional nature
of metallic bonding combined with the absence of local charge-neutrality
requirements.