Change here the visual aspect of an atom (or list of atoms,
previously selected with Atom->Select, when 
Global is pressed).
Parameters for empty entries or 
Local choices remain unchanged.
Style
The 
Style option menu is to select the atom visual representation.
Currently supported styles are: 1) a sphere, for 
Solid; 2) a cross, for
Wired. The sphere gives a hight visual quality, when coupled with lights
and perhaps a perspective projection. A sphere uses considerable screen space
though and is time consuming.
The cross uses much less screen space and computing time. Moreover, when atoms
are bonded, crosses are not represented at all, and atoms are identified just
by the ends of the bond lines, decreasing even further computation needs.
However, wired objects do not have a 3D representation, so diffuse and
specular lights are not reflected, becoming poorly visible when using
lights, unless the ambient component is important, about (0.5, 0.5, 0.5).
Size
In 
Solid mode, this parameter controls the size of the atom spheres.
Combining atom 
Size and 
Variancy with bond 
Size, it is
possible to obtain a wide range of styles to represent atomic structures.
In 
Solid mode, the default is to represent atoms as constant
spheres (
Variancy = 
0.0 and 
Size = 
0.8),
slightly larger than the bonds (
Size = 
0.5). An elegant
style is to represent atoms as constant spheres with the same 
Size
as bonds (
0.5).
To represent compact cristalline structures, atom 
Size
and 
Variancy must be 
1.0, to be consistent with
cell dimensions. This style can also be used to represent molecules,
in order to emphasize the atomic radius and electronic distribution.
To change the default 
Size select 
Atom->Config.
Variancy
The intrinsic size of an atom is given by:
Size x (Variancy x Radius + (1 - Variancy) x Min)
where 
Radius is the atom radius and 
Min is the minimum
radius, by default the H covalent radius (currently 0.37). To change
this default select 
Atom->Config.
In 
Wired mode, 
Variancy is always 
0.0 so
all atom crosses have a constant size, given by 
Size x 
Min.
In 
Solid mode, when 
Variancy is 
0.0 the atom spheres
have all the same size, when 
Variancy is 
1.0 the atom spheres
are scaled directly by the atom radius.
R, G, B
The 
R, 
G, 
B entries define the atom color,
from black (0.0, 0.0, 0.0) to white (1.0, 1.0, 1.0).
Scale
Set the atom size, including its child objects. Atom objects are
scaled around the atom center. The visual representation of an object
is always scaled by its own scale factor multiplied by the scale factor
of all its parent objects until layer, inclusive.