Please consider supporting Autocad Lite and Autodesks drawing viewers.
Though not a 3D program, Autocad Lite can view 3D drawings. A SpaceNavigator makes panning and zooming 2D drawings very easy.
Using a navigator with 2D drawings in Autocad has helped me overcome RSI (repetitive strain injury), and I assume many Autocad Lite users could benefit, too.
Thanks.

