Hi Burr, just another example - you can generally use Perp/Perp to find things like closest or furthest points between things.

Here for example I'm drawing a line and using it to find the shortest line available between these 2 curves:



To use it you need to have picked the initial point somewhere in the general neighborhood of the actual spot, something like within 100 pixels or so.

Then there will be a target snap location calculated on the second curve, and if you move your mouse to target that one, it will get the special "Perp/Perp" snap.

Usually the perp/perp target point is just a little bit past the "single perp" one. There will usually be several different snap points available in that area, so move your mouse a bit slowly around there to see all the different ones.

The single perp one is the perpendicular from the initial point location dropped to the target curve. The double perp/perp one is the shared perpendicular between 2 curves.

There is also a Tan/Tan that works in the same way for tangents.

- Michael