Hi Burr, I don't think that's quite it - from what I could tell he's looking for something like "draw a cline", then move that cline onto a curve snapping it to the particular point on the curve where the curve perpendicular has the same direction as that cline.

You can currently get that "point on the curve that has a specific perpendicular" by doing perp/perp snap currently like this:




He was originally trying to get that same point shown here with perp/perp snap by drawing in a y-axis direction construction line rather than an x-axis direction construction line like you see in the screencap here.

This problem of "find the point on a curve that has a specific perpendicular direction" cannot be solved by just doing a rotation of a construction line - it involves some kind of snap function that will seek through the curve finding the right spot on the curve that has the curve tangent or curve perpendicular going in that particular direction.

- Michael