Len Nemirovsky of Better than Nothing AutoLISP fame shares a trick that he uses to visualize specific parts of a complicated 3D model.
"If you have a relatively complicated 3D model, you can use the Orbit command to view a portion of it. Highlight one or several pieces of your model (assuming that it consists of several solid pieces) with grips, then hold the Shift key and use your mouse to initiate the Orbit command. While moving your mouse, you will only see the highlighted part of the model, and the rest of the model will be invisible until you stop."
Notes from Cadalyst Tip Patrol: Most tools and commands are meant to fill specific roles, but can also present other uses. Holding the Shift key down while pressing the scroll wheel on the mouse invokes the Orbit command. If you select an object or objects before doing this, then the selected object will be visible during the Orbit command, while everything else remains hidden.