From: John Stone (
Date: Fri Feb 12 2010 - 00:26:09 CST

  Have you implemented VMD tracker subclass(es) for your 3-D tracker?
I would begin by doing that, otherwise you may be way off in
your coordinate system. If you have a tracker subclass implemented,
then you should be able to use the various "tool" modes in the
VMD tool menu to see the position of your tracker on the screen,
and to interact with button events etc. Once you have that sorted
out, you could implement other interactions beyond what's already there.
Without seeing the entirety of the code you've written, it is difficult
to judge what you're having trouble with. Unless VMD is actually drawing
the pointer for you via the normal class hierarchy, I cannot say
whether what you're seeing on the screen with your pointer
is even relevant as far as the pick calls go. If you can provide me
with the code you're working with, I can try and give you suggestions
for solving your problem as time allows.

  John Stone

On Mon, Feb 08, 2010 at 10:57:03AM -0600, Dipesh Bhattarai wrote:
> Hello all,
> I am trying to select subset of the molecule using a 3D pointing device.
> The device is tracked by Intersense IS-900 tracking system and is accessed
> through VRPN. I am using VR Juggler to tie the VMD with the multiprojector
> display and the device. I call app->pickList->pick_check() method to see
> if there are any atoms near the current position of the 3D pointing
> device. Even though the location of the cursor looks to be overlapping,
> the method does not actually return anything. Sometime it seems to select
> something, but the picked items does not actually correspond to the item
> near the cursor position. I believe it is because the tracker position and
> VMD use different coordinate systems.
> How do I transform the 3D cursor position so that it correspond to the
> coordinate system VMD use? I would appreciate any pointer to the solution.
> Thanks,
> Dipesh
> --
> Dipesh Bhattarai, PhD

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