Attached is a draft copy of Clothoid2pt, which draws a clothoid between two picked points.
Please consider it a test version. There are comments in the script.
The script does not function properly if points are selected in the "Right" view.
This seemed strange, because the Front view worked well.
So the script has a bug, or else maybe var cplane = pointpicker.ptframe; has a problem in the Right view?
The spur gear script uses this cplane, pintpicker.ptframe, but the circular symmetry could be masking a problem?
Are there any other scripts which plot a curve, using pointpicker.ptframe?

This script took a lot of hard work, but was fun and a very good learning experience.
Due to installing windows 7 on a new hard drive, because of severe clutter in the old windows 7 install, did not test it on MoI version 2.
It has not been tested on a Mac.

Thought about adding a selection for angle variation in degrees, to produce a family of curves.
Did not figure out "recurrence" mathematics. The composite simpson integration could likely be done with adaptive simpsons?

I also made up a tangent selection version, but the ending tangents did not quite match up with the initial selected tangents, probably
due to Fresnel estimation, because the clothoid curve cannot be exactly plotted in NURBS.




Edit May 10, 2013. Removed one comma. The script now runs in Moi2, with same "limitations."
Edit May 10, 2013. Reposted script with Michaels corrections. Script runs well in Top, Front, Back, Right, and Left windows, if both points are picked
in the same window. For 3D view, some additional "plane restriction" is still needed.

Edit May 11, 2013. Added "GetCircle" behavior for selecting points in two different views. The end point is selected first, then the start point.
Edit May 13, 2013. Made two slight changes. Modified cplane z value of ending point to match clothoid curve. Also selection of 2 points in 3d view
with different z values, and same x,y values caused a nonfatal Moi error, so now, if 2 such points are selected, return occurs, time to pick 2 new points.
Was not able to use the Alert message in the if statement.