Leaderboard

I tried to reproduce the issue, and the "tangent" point is (in my case at least) calculated from the endpoint of the original line. I thought the Perpendicular snap would do what the OP wants, but it doesn't register anywhere on the arc. Strangely enough, you can draw a line perpendicular to an arc. I agree with Eldon, a temporary line should help to find the right point. Anything else adds complexity.

@Eduardo Celiz I tested the same code and it works for me. Try testing out putting the cuix file in a different path on your computer, such as a sub-folder in your "documents" folder. Windows does not like customization files stored in the "Program Files" folders. I don't store my customizations in the "Program Files", because any files you want to write back to will error out.

Thank you all! And thank god for this Recover command really a mistery what happened here

Students need to complete at least one elective project. One is all that is required. There is no need to complete two.

Try this. Modified lisp slightly (defun rh:get_elev ( msg / ss rtn) (prompt msg) (setq ss (ssget "_+.:E:S" '((0 . "TEXT")))) (cond ( (not ss) (initget 3) (setq rtn (getreal "\nEnter Level : ")) ) (t (setq rtn (atof (cdr (assoc 1 (entget (ssname ss 0)))))) ) );end_cond );end_defun ;interpolation function to populate text elevation labels ; written by Nete Laana on 24.01.18 Modified dlanorh 30.04.19 (defun c:INTEL (/ p1 p2 p3 e1 e2 e3 d1 d2) ;define the function intel (while (setq p1 (getpoint "\nPick First Point : "));get the first point (setq e1 (rh:get_elev "\nSpecify First Elevation : ");get first elevation p2 (getpoint "\nPick Second Point : ");get the second point e2 (rh:get_elev "\nSpecify Second Elevation : ");get second elevation d1 (distance p1 p2); calculate total distance );end_setq (command "Line" p1 p2 "");draw the line (setq p3 (getpoint "\nPick Interpolation Point : "); pick desired interpolation point d2 (distance p1 p3); calculate distance a e3 (+ (/ (* (- e2 e1) d2) d1) e1);calculate interpolated elevation );end_setq (entdel (entlast)); delete the line (command "circle" p3 0.15); draw circle to identify point (command ".TEXT" p3 1.2 0 (rtos e3 2 2)); dump e3 as text object (setq p1 nil) );end_while (princ) );end_defun The lisp will now loop and ask for the next "Pick First Point : ". To exit the loop press return or click the right mouse button if it is set up that way.