As the user drags the mouse, it acts as a virtual trackball , allowing the user to rotate around all three axes simultaneously. Experimentation with this technique is the best way to learn how to use it. Scaling can be thought of as translation along the Z axes. By pressing and holding the right mouse button and dragging the mouse, the scene with either appear to get closer to the user or farther away, depending on the mouse movement. This allows the user to bring the scene closer to inspect an area more closely, or to move the scene away to get a broader idea of the entire dataset.
Subsets are cubic volumes in the three-dimensional scene created by the user.
If any subsets exist, glyphs lying outside the subsets never get drawn. If a single subset exists, only glyphs within that subset get drawn. Subsetting with the mouse is substantially different than subsetting with the trackers. Since the trackers are inherently three dimensional, and the mouse is not, we need to decompose the three dimensional task of creating a subset into two dimensions for interaction with the mouse. The solution is to hold down the shift key while pressing and move the mouse.