From: Axel Kohlmeyer (
Date: Mon Apr 22 2013 - 02:42:08 CDT

hi olaf,

On Mon, Apr 22, 2013 at 8:44 AM, Olaf Lenz <> wrote:
> Hash: SHA1
> Hi Farrokh!
> On 04/21/2013 05:33 PM, farrokh yousefi wrote:
>> Can VMD displays ellipsoidal particles?
> As Axel already wrote, VMD cannot do so directly. instead, you would
> have to combine other graphical objects to display an ellipsoid.
> If you are mostly interested in displaying the director of the
> ellipsoid, I have started a VMD plugin "moregraphics" that contains
> routines to create more complex graphics from graphical primitives, like
> for example arrows, double cones or two spheres with different colors
> that overlap each other:
> If you need more than that, you need to think about how to triangulate
> the surface of an ellipsoid and use triangle primitives to create it. It
> might be, however, that computing the surface points might become pretty
> slow when doing it in Tcl.
> If you do so, I would be happy if you could add that function to the
> "moregraphics" plugin!

please find attached a piece of Tcl code that i wrote a while ago
which does exactly that kind of triangulation for ellipsoids with
adjustable resolution and using trinorm instead of triangle even. i
don't have the time to integrate it into your package, but it
hopefully is documented well enough to be adaptable.


> Olaf
> - --
> Dr. rer. nat. Olaf Lenz
> Institut für Computerphysik, Allmandring 3, D-70569 Stuttgart
> Phone: +49-711-685-63607
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Dr. Axel Kohlmeyer
International Centre for Theoretical Physics, Trieste. Italy.