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.
Link
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.