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Frequently Asked Questions
Note: recently added items are flagged with
(NEW)
General
GUI problems
TIFF/.pcx files
.EPS and .WMF files
MS-WIN version
General
Q: With respect to some special details the behaviour of
SCHAKAL seems to be rather weird. Do you agree?
A: No doubt about it. Actually, you either might have found a new bug (hitherto
unknown to me) or you just encountered another example of unskilled, suboptimal
programming. Please
e-mail me in such a case. Also have a look at the other FAQ sections,
below.
Q:
The generation of H bonds by {cryst / bld+h} and {cryst / bld+hp} works correctly in many cases,
but sometimes wrong H bonds are generated; in other cases, some
H bonds are missing. What about this?
A: Several bugs in the H-bonds-finding routines have been removed from the
program over the last 5 years.
I wouldn't bet my life though that these routines are absolutely
free-of-bugs, by now, as H-bonds don't belong to our daily business.
Note that the detection of a H bond requires that the H atom in question
is positioned at a more or less reasonable position: a H bond is generated
only when the H---Donor distance is of suitable length. Length ranges for
the different donors can be adjusted in the file addhb.scf (each range
has to be modified several times).
C-H---Donor bridges are not generated by the program.
Q:
How can I stop drawing once it has started?
A: By pressing the <ESC> key on the keyboard. Any time, the string "<ESC>"
appears in the 4th row of the GUI, the current action can be terminated by
pressing this key. If only "ESC" appears, the current action can also be
terminated by clicking the {ESC} button with the mouse.
Q: (NEW)
Lines representing unit cell edges sometimes are too thin or of unequal thickness.
A: This can be overcome by the sequence 'C T *5 A=A' and 'X Q A=A' appended to the
commands to generate the drawing (instead of "5" a different - similar - value may be more appropriate).
Q: It's practically impossible to remember the meanings of all these
cryptically labeled control fields of the GUI. Any advice ?
A: The meaning of a control field (or an individually coloured part
of a control field) is - in most cases - briefly explained if you
click it with the right mouse button.
Q: How can I get rid of these parameter and colour boxes in the
2nd and 3d rows of the GUI once I don't need them any more ?
A: click on one of the two grey buttons just to the left of the large OK button
(the one on the left side).
Q: Why don't these things disappear automatically when clicking
the OK button ?
A: The advantage is that the command in question remains
"latently active". Suppose that you have made a shaded drawing by
clicking the yellow part of { shade }. As the drawing seems to be
too dark, you set a darkness parameter of 0.8
by means of the 'MDF darkness' parameter box.
After the image has been re-drawn (by clicking the red star in { USE }),
you feel that 0.9 would have been a better choice. You now may just
increase the value of 0.8 in the parameter box to 0.9 , click { OK },
and start the next drawing by clicking the red star in { USE }.
And so on, without having to re-generate the 'MDF Darkness'
box after each drawing.
Q:
In the on-screen rotations box the default (wire) model undergoes simple rotations.
If I select a { Q } or { L } etc. drawing, however, the position of the rotation axis
and the size of the model apparently are continuously re-adjusted (i.e., the rotation doesnt
look "naturally"). Is this avoidable ?
A: Yes, just fix the scale factor by clicking somewhere at the unit (consisting of the
control bar and the two control buttons) to the right of the word "scale".
Q: When viewing SCHAKAL's TIFF files with some other software,
the images look o.k., some times, but some other times, I get
these strange grid-like patterns. Any comments?
A: (NEW)
Use a larger resolution via the { resxn } procedure (2 or 3 times the
screen resolution should do in most cases). Read such a file with enhanced
resolution into an image processor
(I use the freely available Micrografx' Picture Publisher 10 [PP10]). Convert the
image into an
RGB-colours image and apply a soft-focus effect (lowest intensity).
That generally highly improves the quality of the images.
Notes for users of PP10:
- Under Windows 7, the image is visualized incorrectly. The following
procedure works anyway:
- Use the items a) transform / convert into / RGB colours; b) effects / soft-focus
- For the soft-focus effect, I use the following (non-optimized) parameters:
Contours: all/7; Unsharp mask: 2/100/0; scatter: 5; stripes: 30/50/10/10;
radial: 30/10/10; zoom: 50/10/10; Gauss: 1; soft: mean/2 (in the genuine
English version, the group names may be different).
- don't save the image, but use 'save as' and select the 'Tagged Image File Format (*.tif)'
option in the first half of the list!
Q: TIFF Images taken from the screen are of poor quality when printed
in a medium or large format. This is
especially true if pellucidity effects have been used. What to do?
A: (NEW)
Use the same procedure as described in the previous answer.
Q: Can I convert a printer drawing into a TIFF/.pcx image?
A: Not with SCHAKAL.
Q: Can SCHAKAL read TIFF or .pcx files from other sources ?.
A: No. The same is valid for HPGL, EPS or WMF files.
Q: TIFF/.pcx images, when restored or printed, show atoms
with ugly white spots. What to do?
A: This happened on some Win32 systems with older program versions.
Use the command 'G D ! 3'. If this helps, you can insert the command into the file
sch99.ini (using a text editor). The versions released after April 2001 are
supposed to be free of this problem.
Q:
We use .EPS and/or .WMF files to generate line style drawings. However, the lines
in these drawings are rather broad. How can we get thinner lines?
A: This can be achieved by means of the 'Set Resolution ...' command.
With the 1st parameter the lines in .EPS files can be controlled, the 1st and 2nd parameters
affect line widths in .WMF files. Examples:
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S R .012
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S R .011 4
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(for .WMF file; default parameters are 0.025 and 10)
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Note that the reduction of the resolution parameters will blow up the drawing times and file sizes
especially for smoothly shaded drawings!
Once suitable resolution parameters have been found (say, the values given above) they could be
made permanent by inserting the commands 'G D ! 603 .012'
(EPS) or 'G D ! 703 .011 4' (WMF) into the
file sch99.ini .
Q: (NEW)
On my new computer running under MS-Windows 7 (64 bit) the program crashes
A: You will find a fix in the DOWNLOAD section
Q: (NEW)
Sometimes an Input file generated by 'Use Xtaldat n' and with "=" specified as a file name
cannot be found later on. In the 'open file' window the name of the file contains
a number of blank spaces. What's wrong?
A: The pathname of your Xtaldatfile is probably too long. SCHAKAL has originally been
written at a time where file and directory names could have a length of maximally 8 characters.
The subsequent changes in this philosophy over the years have been accounted for in the code,
in principle, but obviously not good enough for all "modern" cases.
Be also aware of the
fact that names of files and directories used by SCHAKAL must not contain any blank spaces!
Q: Why do the scroll bars in the built-in editor work incorrectly ?
A: This is (probably) a bug in the compiler system which is the link
between SCHAKAL's FORTRAN source code and Windows.
(NEW)
If you want to use another
editor from within SCHAKAL: Just replace the last line of the
file SCH99win.ini in the SCHAKAL main directory by the name of the desired
editor (e.g. notepad.exe).
Copy the editor into the SCHAKAL main directory or specify instead the
complete path of the editor (e.g. C:\Windows\system32\notepad.exe).
Q:
Which is the best way to make printouts on a LaserJet 3-6 or a
fully compatible printer?
A: Don't use the Windows Printer (Device no. 8) in this case, but use
device no. 4 . Per default, this device (like devices 3,5, and 6)
assumes, that the printer is
connected to your computer by the LPT1: interface. If it is another
interface, or if the LaserJet is accessible via the net, use the
command 'U P -104 "xxxxxx" '
to redirect the printer output. Example:
U P -104 "\\server2\printer1"
Once this is working you might insert the command into the file
sch99.ini.
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