Camera panning (or something like it)

Hi,

Please excuse in advance my "3d newbiness", as I might be missing some
obvious background knowledge, or my question not be totally clear.

I am rendering a complex point cloud scene and while the default zoom
and spin mouse interface is working well, I find that I miss the
ability to pan the camera (or the scene) to obtain a better view.

I have played with what I found in many example programs (i.e.
modifying the scene.center vector in a simple way), but it's never
exactly what I need. The only reference I found to what I (possibly)
need is on this page:

http://vpython.org/webdoc/texture-opacity-lighting.html

where they mention a new "pan" mode. But then it doesn't seem to be
implemented in the version I'm running, which is 5.12 on Ubuntu 10.04
64-bit.

And finally, I'd like to know if there are some settings that could
enhance VPython's performance on my non-3d-accelerated laptop.

Best regards,

Christian

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