Q) I just tried the TRIM command and none of my lines are being trimmed. I followed the manual and it just does nothing. Why is this?

A) If you have drawn your linework in full 3D, meaning you have elevations assigned to the ends of the lines, then the 2 lines probably do not intersect so the trim command will not work. The lines must both be drawn at the same elevations. Please see our technical note about drawing 2D vs. 3D.