@gaieus said: There is a "Film and stage plugin" for SU - although originally it was written for version 5 and has not been upgraded AFAIK but I think it should work on later versions, too): http://sketchup.google.com/download/previousplugins.html (scroll down to it). I think it can do what you wish here. I downloaded it and have been playing with it. Documentation seems to be a little thin. I'm still determining if some strange behavior is normal or if there are problems with it with SK7. But it's showing great promise for what I'm trying to accomplish. Thanks! drew

@drewgandy said: For instance, if I have a "diagonal line" that I want to draw a rectangle against, how do I do it? Sometimes the Ruby Console (billed as a programmer's tool for writing plugins, but I like it for modeling) answers your need. Try diving into Chapter Two, Ruby Console. The first project there is the main and jib on a sloop. The main is orthogonal, the jib is not. Both are easy because any three points are always coplanar. Your four-point rectangles must be coplanar. The second project there adds a rectangle for the bottom of a banister: an example of a rectangle at an odd angle.