AutoCAD LT 2012 includes a small improvement to the Perpendicular and Tangent object snaps that I think might go unnoticed if it weren’t pointed out, but could still be helpful for those of you who need it.
When you’re grip-stretching a line or polyline and using the Perpendicular object snap, you now get two options for the snap point.
First, you can make one of the segments perpendicular to another line.
Or you can make the stretching vector perpendicular to another line.
In earlier versions, you’d only get one or the other, but now you can have both.
A similar principle applies to tangent snaps too. You can either grip-stretch a line so that it becomes tangent to the arc or circle, or the stretching vector can be the tangent instead.