Subject: "Kittel, Chapter 1" as virtual reality world available
From: vogelges@london.physics.purdue.edu (Ralf Vogelgesang)
Date: 5 Dec 1996 18:10:11 GMT
Ok, so I had a little spare time on my hands over thanksgiving. I'd
always wanted to learn the basics of VRML...and while doing that I
figured
I'd create something useful to a more general audience.
What came out is an interface which allows you to create virtual
reality worlds (x-vrml) displaying several of the basic properties
of fundamental crystal structures.
you can display:
- SC, BCC, FCC, or HCP; with mono- and diatomic bases; identical
and different elements. (in other words: you get zinc blende,
diamond, wurtzite, NaCl, CsCL, W, Cu, and sc crystal types)
- from 1x1x1 to up to 7x7x7 repetitions of...
- primitive or conventional unit cell (I recommend you
start modest, though! Most currently available browsers
choke on the high number of objects beyond 3x3x3...)
- additionally you may display the unit cells as (transparent)
"hulls" around each atomic constellation, or just at the origin.
- and you may hide atoms and/or bonds for clarity.
of course, you also may choose to display coordinate axes and lattice
vectors.
I hope, my interface is completely proof-tested, ready to go public,
and will be enjoyable to others. It's aimed to be as easy-to-use as
possible, while providing all the variety you need to SEE the subtle
differences between wurtzite and zinc blende, say.
You must have a vrml-capable web-browser, or at least a standalone
vrml viewer! (find all sorts of vrml-related info at the VRML
repository, http://rosebud.sdsc.edu/vrml/repository.html) Then direct
your browser to:
http://www.physics.purdue.edu/~vogelges/diamond.html
I definitely want to hear about your opinion! If you like it, and you
have some suggestions for adding simple but helpful features (there
are super-general solutions out there, already...I don't strive to
imitate anything like a full-blown ball&stick; modeller!-)
let me know! Cheers, rafl
--
* * ralf
*Q *
*_/|- maintainer of the soc.culture.german FAQ:
/ !
Subject: Re: "Kittel, Chapter 1" as virtual reality world available
From: Armel Le Bail
Date: Fri, 06 Dec 1996 09:33:52 +0100
Ralf Vogelgesang wrote:
> Ok, so I had a little spare time on my hands over thanksgiving. I'd
> always wanted to learn the basics of VRML...and while doing that I
> figured
> I'd create something useful to a more general audience.
..........
> You must have a vrml-capable web-browser, or at least a standalone
> vrml viewer! (find all sorts of vrml-related info at the VRML
> repository, http://rosebud.sdsc.edu/vrml/repository.html) Then direct
> your browser to:
>
> http://www.physics.purdue.edu/~vogelges/diamond.html
>
> I definitely want to hear about your opinion! If you like it, and you
> have some suggestions for adding simple but helpful features (there
> are super-general solutions out there, already...I don't strive to
> imitate anything like a full-blown ball&stick; modeller!-)
>
> let me know! Cheers, rafl
That's fine. Just one problem. The size of some the VRML files
may outpass the capacity of a Pentium 90MHz, 16Meg RAM, 2 Meg
video. The charge in number of polygons is due mainly to spheres
(50-100 polygons per sphere) or cylinders. An option wireframe
would lead to smaller files.
--
Armel Le Bail - http://fluo.univ-lemans.fr:8001/
Subject: Re: Looking for 3-dim mixed radix real to complex FFT
From: Ingo Steller
Date: Fri, 06 Dec 1996 08:37:52 -0500
Ralf W. Grosse-Kunstleve wrote:
>
> Hi!
>
> I'm looking for FFT procedures (C or Fortran) with these
> characteristics:
>
> Real to complex (and vice versa)
>
> 3-dimensional
>
> Any NX, NY, NZ possible
>
> I'm using the SGI complib.sgimath library procedure "sfft3du",
> which exactly matches my needs. But, of course, the source code
> is not available.
>
> Any help in finding source code to replace "sfft3du" is very
> much appreciated!
>
> Ralf
The following WEB-page has a collection of various FFT routines. I found
it very useful:
http://www.spektracom.de/~arndt/fxt/fxtpage.html
Ingo.
--
+------------------------------------------------------------------------+
| Ingo Steller
|
| Department of Biological Sciences
|
| 1392 Lilly Hall of Life Sciences
|
| Purdue University
|
| West Lafayette, IN 47907-1392
|
| USA
|
| |
| Phone: ++1-317-494-4507
|
| Fax: ++1-317-496-1189
|
| E-mail: steller@utah.bio.purdue.edu
|
| URL: http://www-structure.bio.purdue.edu/~steller/
|
+------------------------------------------------------------------------+
Subject: Re: C routines for pointgroups
From: kosten@pc21.xtal.rwth-aachen.de (Klaus Kosten)
Date: Fri, 6 Dec 1996 16:48:48
In article <32A6E7E1.2781@indi.aci.uni-heidelberg.de> Stefan Reichling writes:
>From: Stefan Reichling
>Subject: C routines for pointgroups
>Date: Thu, 05 Dec 1996 16:18:57 +0100
>Hello,
>I'm looking for C routines which are able to do the symmetrie operations
>with respect to the given pointgroup.
>steve
>--
Look for "xtal4pov.zip" on
ftp.informatik.uni-oldenburg.de/pub2/pov-ray/gen/pc/
ftp.uwa.edu.au/pub/povray/utilities/
achat.xtal.RWTH-Aachen.DE/pub/graphics/povray/
This archive contains the DOS executable, the C source, and sort of a
tutorial for generating all symmetry equivalent faces from a Hermann-Mauguin-
symbol and one face. Output is a POV-Ray compatible ASCII-File.
Hope this helps,
Klaus
--
--
Klaus Kosten
Institut fuer Kristallographie
der RWTH
D-52056 Aachen, Germany
E-Mail: kosten@kristall.xtal.rwth-aachen.de
Subject: Re: "Kittel, Chapter 1" as virtual reality world available
From: vogelges@london.physics.purdue.edu (Ralf Vogelgesang)
Date: 6 Dec 1996 16:41:35 GMT
In article <32A7DA70.5BC9@fluo.univ-lemans.fr>,
Armel Le Bail wrote:
>That's fine. Just one problem. The size of some the VRML files
>may outpass the capacity of a Pentium 90MHz, 16Meg RAM, 2 Meg
>video. The charge in number of polygons is due mainly to spheres
>(50-100 polygons per sphere) or cylinders. An option wireframe
>would lead to smaller files.
True, that's why I am already providing the optional substitution
of spheres for cubes and cylinders for parallelepipeds ;-) If you
check my page, you should find in addition the option
to draw bonds and atoms non-interpenetrating. All this does _some_
good, but I'd still like to represent 7x7x7 cells on a regular pentium.
I am not aware a true wire-frame option in VRML. Bear with me, I'm only
just beginning to explore the language. From what I found on the net,
it seems to me that this is an inherent problem of VRML -- the current
desktops are simple not quite up to large worlds. (I'm suffering from the same
problem, btw.)
If you have a piece of VRML code for reference that reduces the impact
of the too-many polygons, please pass it on -- I'd be delighted to
incorporate it!
cheers, rafl
--
* * ralf
*Q *
*_/|- maintainer of the soc.culture.german FAQ:
/ !
