Interactive clipping plane In this question, How can I easily animate cutaway views on multiple objects? it was suggested to use the camera clipping distance as a cutting plane. 



Is there a way to have an interactive cutting plane that is not parallel to the camera?

What is needed is a way to review complex geometry in real time by moving a cutting plate through the geometry in a way that does not necessarily line up with the camera view clipping planes.
For use in the viewport, try the clipping border AltB: