AboutScott Cook Expertise I`ve been using AutoCAD since 1987 and programming AutoLISP nearly as long. I can answer questions about programming AutoCAD (except ARX) and production enhancement techniques. I cannot answer questions about AutoCAD crashes or DWG corruption. AutoCAD PROGRAMMING (menus, lisp) related questions only!
Experience Since 1987. Author of Plot2000 software for for AutoCAD, http://www.plot2000.com.
PROGRAMMING QUESTIONS ONLY PLEASE. Questions that are NOT related to programming or AutoCAD customization (menus and lisp only please) are outside the scope of my volunteer services and will NOT BE ANSWERED.
Question Within a lisp, can you select an arc and then call up it's length for calculations?
Answer sure. look at the dxf reference in the online help for the entity codes which you can retrieve with the entget function. you'll need the starting and ending angle, which are stored in radians in a counterclockwise direction. you'll need some special case scenario if it passes thru 0 degrees, like adding 2pi to the end angle.
you'll need to write your own code to extract the start and end angle, but it will be something like this (untested):
(setq start_ang (cdr (assoc 51 (entget (car (entsel)))))
