Another Break Objects Quickly AutoLISP routine

In my earlier “Break objects quickly” tip, I have 4 routines that help you break objects more quickly than the standard AutoCAD command.

Febien Mosen sent me another routine, SCISSORS, that has 3 features:

• You don’t need to preselect the object; you just click the point where you want to break
• Only if there are more than 1 object under the break point (that is, if you click on the intersection of objects), does the command as you to select which object you want to break

I tested it and it worked fine for me.

You can download the AutoLISP file here.

Here’s the code:

(defun C:SCISSORS( / pt1 bpt1 bpt2 ss1 dist1 ent1 centrecercle)
;;make it quiet
(setvar “cmdecho” 0)

;;first, get the breaking point
(setq pt1 (getpoint “Give me the break point… “)) ;;point where to break

;;now, check if there’s more than one object under that point
(setq ss1 (selectfrompoint pt1))

;;if there’s more than 1 object under point, ask to select, else use existing point
(if (> (sslength ss1) 1)
(progn ;;then
(princ “DISAMBIGUATION : pick the object to break…”)
(setq ent1 (entsel))
(setq ent1n (car ent1)) ;; e-name of ent1
(setq bpt1 (cadr ent1)) ;; point on ent to break
)
(progn ;;else
(setq ent1n (ssname ss1 0));;store into an entity (can be useful further)
(setq bpt1 pt1) ;; point on ent to break
)
)

;;but if it’s a circle (thus usually unbreakable)…
(if
(= (cdr (assoc 0 (entget ent1n))) “CIRCLE”)
;;then replace the circle by 2 arcs joining at the break point
(progn
(princ “It’s a circle !”)
(setq centrecercle (cdr (assoc 10 (entget ent1n))))
(command “_arc” “_c” centrecercle pt1 “_a” “180”)
(command “_arc” “_c” centrecercle pt1 “_a” “-180”)
(entdel ent1n)
)
;;else perform a normal break
(progn
(command “_break” bpt1 “_f” pt1 pt1)
)
)

;;restore cmdecho
(setvar “cmdecho” 1)
;;end quietly
(princ)
)

;;— this function makes a selection set of entities beneath a point
(defun selectfrompoint (bpt1 / dist1 ss1)
(setq dist1 (/ (getvar “viewsize”) 200)) ;; set a distance equal to 1/200-th of view height
(setq ss1 ;;select by fence around point
(ssget “_F”
(list
(list (+ (car bpt1) dist1) (+ (cadr bpt1) dist1) 0)
(list (- (car bpt1) dist1) (- (cadr bpt1) dist1) 0)
)
)
);; setq ss1
ss1
)

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Ellen Finkelstein

Ellen Finkelstein is the author of the best-selling AutoCAD & AutoCAD LT Bible, which started with R14. Ellen has written extensively on AutoCAD, including articles for Autodesk’s website and features for AutoCAD’s Help system. Ellen’s first book was AutoCAD For Dummies Quick Reference.

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