VMD provides optional support for Spaceball six-degree-of-freedom input devices. The Spaceball may be used to rotate, translate, and scale molecules, using up to 6 control axes simultaneously (3 axes in translation, 3 in rotation). The Spaceball can be used independently and simultaneously with the mouse. With the spaceball in one hand and the mouse in the other, a user can perform complex picking and identification operations more efficiently, since the mouse can be left in pick mode (for example) while the Spaceball is used to perform rotations, translations, and scaling operations with the other hand.
The Spaceball can be run in one of several modes within VMD. The Spaceball interface currently provides two methods of rotation and translation, and a scaling mode. The Spaceball interface currently uses Button 1 (known as Function 1 in the SpaceWare driver) to reset the view, and Button 2 to cycle through the available Spaceball interface modes.