By default the drawing will be surrounded with a rectangular box outline. This setting
may be changed with the ON and OFF sub-keywords. The structure is drawn with a
shrinkage factor of 90 percent relative to the automatic scale factor that fits the drawing
within the BOX-outline to provide a margin. This default percentage may be changed
with the SHRINK shr option. This option may be also of use when a drawing which a
non-default scale is required. The three numbers shown in the bottom right, top left and
bottom left corner of the box are the cumulative rotation angles xr, yr and zr
respectively. These numbers may be used to reconstruct this particular orientation in
a later session directly from the default UNIT orientation via a VIEW UNIT XR xr YR yr
ZR zr instruction. The default horizontal to vertical size ratio of the box is 4/3. A ratio
of 1.0 results in a square box.
Example:
BOX RATIO 2 SHRINK 80
BWC TYPE
An alternative to color coding of atom types is a distinction of atom types with different
patterns drawn on the spheres representing the atoms. This is useful for
black-and-white hardcopy and publication drawings. The current (default) settings may
be inspected with the LIST TYPES instruction. Available options for bwc are contour,
net, shade, segment, dots, black, cross, parallel, globe, meridian, horizontal, vertical,
mesh, diagonal, slant, textile and void.
Example:
BWC TYPE Pd GLOBE
COLOR
This instruction may be used to change the default colour (normally BLACK for plotters
and WHITE for terminal screens) of the plot into the one chosen (subject to the
availability of colour with the actual graphics facility). This colour is used for bonds,
atom circumference and text.
Example:
COLOR RED
COLOR TYPE
The color setting of an atom-type, as shown with a LIST TYPES instruction, may be
modified with the COLOR TYPE instruction. The color code is a two-digit number, one
digit for the color to be used for the odd-numbered lines and one digit for the
even-numbered lines.
0 = blanc, 1 = black(white), 2 = red, 3 = green and 4 =blue.
Example:
COLOR TYPE C 01 O 22
CPK
SEGMENT/BLACK/BWCOL/DOTS/GLOBE /CROSS/PARAL/MERID) (STICK)
(SPOT)
This sets parameters for a space-filling model (Corey-Pauling-Koltum) with atomic radii that are taken by default from internal tables and optionally with RADII ATOMS instructions. The surface may be either globally Shaded, Coloured, Dotted, drawn with Contours, segments, a Net structure etc. or with a pattern dependent on the atom type (BWCOL). The keyword SHADE causes the drawing of shade lines representing shadow from a light source whose position is given by the two angles a1 and a2. The setting of both angles to zero models a light source coming directly towards the viewer along the ZP axis, so that the whole atom is shaded. The angles a1 and a2 are rotations of the light source about YP and ZP respectively and in that order, and d is the spacing in cm between shading lines. Default settings are 120, -45, 0.15.
The atoms may be coloured as a function of their atom type. This feature is
implemented as the SHADE option with a1=a2=0 and d = 0.05 in the absence of other
sub-keywords with the COLOR sub-keyword. The NET sub-keyword produces a NET
with two sets of perpendicular great-circles drawn on the surface (colored in
combination with the COLOR sub-keyword). the number of horizontal and vertical
circles may be modified with nh and nv. The GLOBE sub-keyword produces a polar grid
surface, combined with shading. The CONTOUR sub-keyword produces a set of
parallel circles on the surface. The BWCOL sub-keyword may be used to differentiate
between atom types in a black-and-white plot. The SPOT sub-keyword asks for a light
reflexion spot on the surface. The STICK keyword produces a CPK plot combined with
a STICK frame to show the chemistry of the molecule.
Example:
CPK NET COLOR SPOT
MONO
A single perspective drawing is to be produced as seen from a point at d cm. along the ZP axis, above the centre of the drawing. The default setting is 10000 cm. (effectively infinity) but may be set to 60 cm. for convenient perspective viewing. The actual value is plotted in the top right corner of the plot (zero for infinite perspective) to avoid confusion.
OVERLAP
The overlap margin (non-bonded bond-bond, atom-atom, atom-bond overlap) is set by
default to the value mrg = 0.1 cm and the incoming bond shadow margin to shad = 0
cm. Overlap calculations (by default) may be turned off for fast test runs. This should
be specified before plotting and after the specification of the plot-style.
Example:
OVERLAP OFF
RADII ATOMS
This globally sets the atomic radii (Angstrom) for the plotting of the spheres in the SOLID, ROD and CPK style. The appropriate instruction is normally executed automatically. In the SOLID and ROD mode spheres are drawn at 0.5 times their covalent radius and in the CPK mode at the covalent radius + 0.8.
RADII ATOMS
This instruction may be used to input user defined radii for the spheres to be drawn. The actual values may be listed with a LIST TYPES instruction.
RADII BONDS
Bonds in SOLID or ROD drawings have cylindrical radius r Angstrom (default 0.04 and 0.2 resp.) and are drawn with n (default n = 8) lines along the circumference of the cylinder, spaces (180/(n+1)) degrees apart on the visible side of the cylinder. This instruction resets r and n for all bonds.
RADII BONDS
This sets r and n for all bonds to a particular atom or atom type. This may be useful to emphasize coordination of a particular atom. To produce single-line bonds, set r - 0 and n = 1. Bonds with n = 0 are omitted.
RADII BONDS
This sets r and n for a particular bond already in the connection list.
RADII BONDS
This sets r and n for all intermolecular bonds created by a JOIN RADII INTER
instruction. This is useful, for example, in distinguishing hydrogen bonds.
RADII BONDS ALL not only resets r and n for all bonds, but also cancels all other
RADII BONDS instructions which have already been given, i.e. 'all' really means all. To
reset r and n for all bonds EXCEPT special ones, use this instruction instead.
When the program is drawing the bonds, it looks though the list of the RADII
BONDS instructions and assigns the r and n values of the last instruction given which
is relevant to the bond being drawn. In this way the result of conflicting instructions can
be controlled by the order in which the data card are given. An example of such a list
of instructions:
RADII BONDS ALL 0.05 5
RADII BONDS INTER 0.02 2
RADII BONDS TO CU1 0 1
RADII BONDS TO NA 0.03 2
RADII BONDS CU1 O4 0.06 10
RADII BONDS TO H 0.02 4
RADII BONDS INTER 0 1
RADII BONDS TO H 0.03 7
is equivalent to
RADII BONDS TO H 0.03 7
RADII BONDS INTER 0 1
RADII BONDS TAPER
In order to enhance the perspective effect of drawings (see MONO and STEREO options), bonds are drawn with an exaggerated taper, the degree of exaggeration being set by the parameter t. t = 1 gives maximum exaggeration. The default setting is 0.375. Tapering is applied even if the viewing distance is effectively infinite, unless t = 0.
ROD
DOTS/BWCOL/BLACK/CROSS/PARAL/MERID)/(COLOR (a1 a2 (d)))
(SPOT)
This prepares for a ROD-style plot with atoms optionally shaded, coloured, drawn with a net or contoured surface or individually characterized (see CPK for further information).
SIZE
The default character size (ch = 0.4 cm) may be changed with a SIZE 0 CHAR ch instruction. Similarly, the default character size of the title (ti = 0.5 cm) may be changed with the TITLE sub-keyword: SIZE 0 TITL ti. The other option are not effective as yet.
SOLID
GLOBE/SEGMENT/CONTOUR/SEGM/DOTS/BWCOL/CROSS/PARAL/MERID)
(SPOT)
This gives a PLUTO-type bond and stick plot. See the CPK instruction for other keywords.
STEREO
This produces a stereo pair, as seen by an observer with eye-separation of 6 cm. at a distance d ( default 60) cm along the ZP axis. If the keywords RG or GR are present, the left-eye and right-eye views are superimposed instead of being placed side-by-side, but are drawn in different colors, so that the stereo effect can be observed using appropriate red/green or green/red filters. The sub-keyword CROSSED allows for crossed eye vision.
STICK
This asks for a stick model drawing, i.e. one in which the atoms are points and the bonds single lines. A succession of such drawings requires very little computing and plotting time, and is useful as a preliminary run for checkout and to find a good view direction. Note: since atoms are represented by points in this presentation, as are bonds when viewed along their direction, non-bonded atoms and some linear molecules viewed from the end are not shown in STICK plots.
TITL
The title of the plot is normally taken from the TITL card that preceded the coordinate data. It can be overruled with a new TITL instruction.
UNITCELL
This allows a unit cell outline to be drawn. The outlines are treated as bonds. Their default setting is: rbo = 0.01 and nli = 2