2.6 THE PLOT PROGRAM Z88P
The plot program Z88P plots undeflected, deformed, both undeflected
and deflected structures as well as super structures.
Z88P can plot on the screen or into a file. The plot file contains
so-called HP-GL commands which are used by HP plotters. Of course,
it is optional to process the HP-GL files also in other programs,
e.g. in CorelDraw, WinWord etc. If necessary change the ending
.TXT. E.g. Winword expects the ending . HGL or .PLT for HP-GL
files.
In addition, von Mises stresses can be plotted on the screen
or send to a plotter. The screen colors can be adjusted for Windows
in the file Z88P.COL. The file Z88.FCD for the UNIX operation
system allows for much more possibilities in changing colors and
fonts as well as the sizes and locations of the pushbuttons, radioboxes
etc. You can completely modify the whole appearance of Z88P for
UNIX as you wish.
Needed Files | Super structures | Undeflected FE struc. | Deflected FE struct. |
Z88NI.TXT | Yes | No | No |
Z88I1.TXT | No | Yes | Yes |
Z88O2.TXT | No | No | Yes |
Z88O5.TXT | No | Yes, for Mises stresses | No |
For fastest operation Z88P connects the nodal points with straight
lines, although for Serendipity elements 7, 8, 10, 11 and 12 the
edges of the elements are square or cubic curves.
Note: You can also use your CAD program together with CAD converter Z88X to plot super structures and undeflected finite element structures, yet deflected structures and von Mises stresses do need Z88P. Or convert Z88's plot files (HP-GL language) into DXF files: CorelDraw does a very good job.
Z88P saves the last structure file name, the several factors and
label adjustments in a file Z88P.STO. This file is loaded when
starting Z88P, so that the last structure is restored automatically.
If you like to start with a new structure, the file Z88P.STO should
be deleted before launching Z88P. This can be done with Plot
> Delete Z88P.STO (Windows) or Plot with option
rm z88p.sto (UNIX) in the Z88-Commander Z88COM.
Special key strokes for Windows:
Prior: increase zoom
Next: decrease zoom
Cursor left: panning X direction
Cursor right: panning X direction
Cursor up: panning Y direction
Cursor down: panning Y direction
..And in addition for 3-D structures for Windows:
Home: panning Z direction
End: panning Z direction
F2: rotate around X axis
F3: rotate around X axis
F4: rotate around Y axis
F5: rotate around Y axis
F6: rotate around Z axis
F7: rotate around Z axis
F8: reset all rotations to 0
Under UNIX use the usual X and Motif key assignments: Tab key
and arrow keys for choice and space bar for activation.
Pen plotters draw the undeflected structure with pen 1 and the
deflected structure with pen 2.
Explanation of some menu items:
Name of Structure File:
Windows: File > Structure File
UNIX: Stru. text field directly on window
Choose the structure file here. Enter name, if necessary with
path, press return. The new stucture is loaded and drawn immediately.
Name of Plotter File:
Windows: File > Plotfile
UNIX: Plot. text field directly on window
Choose a plotter file name here. Default name is Z88O6.TXT. The
plot file includes HP-GL commands in ASCII code ready for reprocessing
by other programs, e.g. CorelDraw.
Windows: Serial plotters: A direct output from Z88P to
a plotter does not always work. If necessary, put Xon/Xoff sequence
in Z88O6.TXT with the Z88-Commander after producing Z88O6.TXT.
Then Z88O6.TXT can be send to a serial plotter by
You also can use the Hyperterminal of Windows. Try ASCII, CR-LF
ending, local echo, line delay 10 msec, byte delay 1 msec. However,
large files can cause timeouts. This is a generally poor attribute
of serial interfaces, cf. the notes below for UNIX.
Windows: HP LaserJet: Some laser printers can be
switched from PCL mode to HP-GL mode by hand, for others this
works unfortunately only by software. In this case put a LaserJet
sequence in Z88O6.TXT with the Z88-Commander Z88COM after producing
Z88O6.TXT. Then do normal printing.
UNIX: Serial plotters: Serial interfaces are adjusted
with the stty-command as root
Here /dev/ttyS1 is the second serial interface. The first serial
interface is /dev/ttyS0 . If your plotter needs a software switchover
on protocol Xon/Xoff, start the little utility pxon88 after
the production of Z88O6.TXT by Z88P . Then send Z88O6.TXT as root
to the interface:
You can also put the serial plotter as a raw-device into /etc/printcap directly. Lets say it would be called HP7475A-a3-raw there. As a normal user you can then plot via the UNIX spooling system
Caution: Serial pen plotters are extremely slow devices,
i. e. they can plot a lot due to the very efficient HP-GL language
with extremely little information. For huge HP-GL files this can
have the effect that the serial interface - despite Xon/Xoff -
delivers far too few bytes to the plotter and therefore
gets a timeout. See these general difficulties for LINUX under
/usr/doc/howto at printer-howto and serial-howto.
UNIX: LaserJet: Some laser printers can be switched from
PCL mode to HP-GL mode by hand, for others this works unfortunately
only by software. In this case put a LaserJet sequence in Z88O6.TXT
by the little utility laserj88 after producing Z88O6.TXT
with Z88P. Take care that laser printers have a raw entry
in /etc/printcap as the UNIX spooling system is supposed to pass
the HP-GL files completely unfiltered. Plot using
Notes Windows and UNIX: The HP-GL commands produced by
Z88 work faultlessly on several HP and IBM plotters if the physical
adjustments are fixed correctly. Check out if your plotter is
actually 100 % HP-compatible !
Another predefined file name is Z88O7.TXT. You can store the
undeflected
structure in Z88O6.TXT and the deflected structure in Z88O7.TXT
if you do not want to do it by the Z88P command Structure >
Un- and Deflected. The file Z88O7.TXT can be appended alternatively
to Z88O6.TXT later allowing the plotting of the undeflected and
the deflected structure in one run. Mind the order: Store Z88O6.TXT
first, then Z88O7.TXT. But you can also plot completely different
structures.
Deformation Modes of the Structure:
Windows: Structure > Undeflected, Deflected, Un- and Deflected
UNIX: Radio box Undefle., Deflected, Un+Defle.
Plots the undeflected structure, the deflected structure or both.
Stresses can be plotted only on undeflected structures. When using
Un- and Deflected nodes and element labels are plotted
on the undeflected structure.
Caution Deflected and Un- and Deflected: The user must have executed a calculation of displacements before using this function. Do a FEA run with Z88F before using Z88P. Otherwise, some old files Z88O2.TXT (displacements) from earlier Z88 runs are opened causing totally wrong results !!
Output in Plotter File:
Windows: Output > CRT, Plotter
UNIX: Pushbutton Plot.
Default is plotting on the screen (CRT). Selecting Plotter
produces a HP-GL file whose name has been selected with Interface
at choice. This runs very fast. Z88P shifts back again immediately
to CRT after storing the HP-GL file and after quitting the message
box.
Choice of View:
Windows: View > XY, XZ, YZ, 3-Dim
UNIX: Radio box XY, XZ, YZ, 3D
Select view depending on structure: At 2-dimensional structures
XY, at 3-dimensional structures 3-Dim. Mind 3-D structures: The
desired side views can be shown with XY, XZ and YZ, however, the
nodes and element labels are plottet ascendingly (starting with
node 1 or element 1 ascending to the last node or element), the
stress points in the order of the Gauss points, ascending from
element to element. The finished pictures can therefore show nodes
and element numbers as well as stresses which does not really
lie in the level of the side view! Only 3-D view gives reliable
information. Note: If starting with a "fresh" 3D- structure
in Z88P you will see under Windows the menu hook improperly set
on XY or under UNIX the radio button XY set, because the menus
are built up before reading the Z88 files. Do not care.
Drawing Node and Element Numbers:
Windows: Labels > No Labels, Elements, Nodes, Label All
UNIX: Radio box No Labels, Elements, Nodes, Both
Plot the element numbers or the node numbers or both or skip
numbering.
Labeling can get confusing because, depending on view, different
numbers of complicated space structures are plotted several times
at the same location. Carefully place structure parts by corresponding
rotations.
Coordinate System:
Z88P uses a coordinate system which starts in the center of the
CRT or the center of the sheet. It is fixed as follows:
Axis | CRT min | CRT max | Plotter min | Plotter max |
X | -100 | +100 | -138 | +138 |
Y | -100 | +100 | -100 | +100 |
Z | -100 | +100 | -100 | +100 |
For 3-D structures the transformation of the 3-D coordinates to
the 2-D CRT or plotter is carried out via an isometric view ref.
ISO 5. If the rotation angles ROTX, ROTY and ROTZ are set to 0
respectively, then is valid: X : Y : Z = 1 : 1 : 1. Z points up
and X and Y are tilt by 30 degrees.
Windows: The rotation angles can be modified by steps of
10 degrees with the buttons F2 to F7 or with Factors
> Rotations 3-D in optional values. F8 resets all
rotation angles to 0 degrees.
UNIX: The rotation angles can be modified by steps of 10
degrees with the Pushbuttons RX+, RX-, RY+, RY-, RZ+ and
RZ-. Pushbutton Rot 0 resets all rotation angles
to 0 degrees.
Plots fitting entirely on the screen usually work with the same factors for the plotter. However, because plotters have different X-Y ratios, factors need to be changed slightly for plotter output sometimes.
Global Magnifications:
Windows: Factors > Global Magnifications
Do zooming either in steps with the keys Prior and Next
or delicately with factors FACX, FACY, FACZ. The entry of factors
is also useful if several structures should be plotted using the
same factors.
UNIX: Pushbuttons Zoom+ and Zoom-
Panning:
Windows: Factors > Centre Factors
Do panning into X direction with left and right cursor
keys, into Y with cursor up and cursor down
and into Z (at three-dimensional structures) with Home
and End. Alternatively you can use Factors > Centre
Factors : CX, CY and CZ.
UNIX: Pushbuttons X+, X-, Y+, Y-, Z+, Z-
Enlarging Deflections:
Windows: Factors > Deflections
UNIX: Text fields FUX, FUY and FUZ
Enlarge the computed deflections with the factors FUX, FUY and
FUZ. Default values are 100. Attention UNIX: As usual for UNIX,
the changes only apply at a respective Return. However,
you can type in all three fields without Return and then
press the Pushbutton Regen (for Regenerate).
Rotations:
Windows: Factors > Rotations 3-D
The rotations around X, Y and Z axises are defined with Factors
> Rotations 3-D : ROTX, ROTY and ROTZ. Default values are 0.
With the F2 . . F7 keys the structure can be revolved in steps
of 10 degrees.
UNIX: Pushbuttons RX+, RX-, RY+, RY-, RZ+, RZ-
Turn in steps of 10 degrees. Pushbutton Rot 0 resets the
rotations to 0.
Height Ratio:
Windows: Factors > X-Correction FXCOR
UNIX: Text field FXCOR
With the function X-Correction FXCOR the height ratio can be
adjusted
to the monitor customization. The default values are 0.75 for
NT and 0.85 for UNIX. Modify FXCOR depending on monitor type if
necessary. FXCOR is stored in Z88P.STO for further use.
Von Mises Stresses:
Windows: Mises Stresses > No von Mises stresses, Show von Mises stresses
UNIX: Pushbutton Mises
If you have calculated von Mises stresses by Z88D (only useful and possible for continuum elements of the type 1, 3, 6, 7, 8, 10, 11, 12, 14, 15, 16, 17, 18, 19 and 20) then you can plot the von Mises stresses either into the Gauss points (elements No.1, 7, 8, 10, 11 and 12) or into the center of gravity of the elements (elements No.3 and 6). Possible for CRT and Plotter.
Stresses will only show if you have chosen Structure >
Undeflected.
Z88P otherwise recalls that you wanted to plot von Mises stresses
and shows them when switching from Show von Mises stresses
to Structure > Undeflected.
If you choose Show von Mises stresses and then Output
> Plotter the von Mises stresses are converted into a letter
scale from A to J to match even ancient pen plotters with only
2 or 6 pens or monochrome laser printers.
On the screen the stresses are plottet using a color scale. You
can adjust this color range in Z88P.COL (Windows) or Z88.FCD (UNIX)
to match your personal wishes.
Consult the output file Z88O3.TXT for exact stress results because
Z88P shows stresses only in a 10-step range.
Caution: The operator is responsible for first running a stress
calculation by Z88D before using
this function. Run Z88F or the Iteration solver for calculating the
displacements and then
the stress processor Z88D before starting Z88P.
Otherwise some old stress files Z88O5.TXT
from earlier calculations are read causing totally wrong results
!!
Keep in mind:
Automatic Scaling:
Windows: Autoscale > No Autoscale, Yes Autoscale
UNIX: Pushbutton AutoS
The Autoscale function takes care that structures will completely
fit on the screen.
Autoscale activates automatically if no file Z88P.STO is available
or if a new structure is loaded by File > Structure File.
Autoscale again is deactivated immediately and the hook points
to No Autoscale. If a file Z88P.STO is present the factors
are read from this file. You can then scale properly with Autoscale
> Yes Autoscale. However, Autoscale switches again immediately
to No Autoscale. Autoscale > Yes Autoscale is
a kind of pushbutton. The explanation above corresponds to UNIX
as well.