Find the correct direction of picked two points.

[Dayananda]

I am trying to draw Following type of figure attached. When I am picking 2 points up to down, Down to up Left to right or right to left the red line should be in the correct position. I have written the following lisp codes. But it does not function correctly. Please help me to do this task.

 (setq b_p1 (getpoint "\nPick on 1st beam cl"))
 (setq b_p2 (getpoint b_p1"\nPick 2nd beam cl " ))

(command "line""non"b_p1 "non"b_p2 ""); line bottom part
(setq line1(entlast))

(setq spane1 (distance b_p1  b_p2));;; 1st span
(setq crnkL (* 0.3  spane1));; top line length
(setq gap 200);; gap between top and bottom part of line
(setq angle1 (angle b_p1 b_p2)); angle of line 1 in radiance

(if(and(>= angle1 0 )(<= angle1 (/ pi 2 ))) 
(setq angle2 (+ angle1(/  pi 2)));; angle to point b_p1 from t_p1
); if

 (if(and(>= angle1 (/ pi 2 ) )(<= angle1 pi)) 
(setq angle2 (+ angle1(/  pi 2)));; angle to point b_p1 from t_p1
); if 
    
(setq t_p1 (polar b_p1  angle2 gap )) 
(setq t_p2 (polar t_p1  angle1 crnkL )) 
(command "line""non"t_p1 "non"t_p2 "")

 

[dexus]

How about something like this, is that what you are looking for?

(defun draw (pt1 pt2 len)
  (if (and pt1 pt2 len)
    (progn
      (entmakex
        (list
          '(0 . "LINE")
          (cons 10 pt1)
          (cons 11 (polar pt1 (angle pt1 pt2) len))
        )
      )
      (entmakex
        (list
          '(0 . "LINE")
          (cons 10 (polar pt2 (angle pt2 pt1) len))
          (cons 11 pt2)
        )
      )
    )
  )
  (princ)
)

(draw
  (getpoint "\nFirst point: ")
  (getpoint "\nSecond point: ")
  (getdist "\nLine Length: ")
)

Edited 14 hours ago by dexus

[Tsuky]

This ? in dynamic mode...

((lambda ( / pt1 pt2 gap)
  (initget 1)
  (setq
    pt1 (getpoint "\nPick on 1st beam cl: ")
    pt2 pt1
    gap 200
  )
  (while (equal pt2 pt1)
    (setq pt2
      ((lambda ( / key pt alpha spane crnkL p1 p2)
        (princ "\nPick 2nd beam cl: ")
        (while (and (setq key (grread T 4 0)) (/= (car key) 3))
          (cond
            ((eq (car key) 5)
              (redraw)
              (setq pt (cadr key))
              (setq alpha (angle pt1 pt))
              (setq spane (distance pt1 pt))
              (setq crnkL (* 0.3 spane))
              (cond 
                ((and (>= alpha 0.0) (< alpha (* pi 0.5)))
                  (setq
                    p1 (polar pt (+ alpha ( * 0.5 pi)) gap)
                    p2 (polar p1 (+ alpha pi) crnkL)
                  )
                )
                ((and (>= alpha (* pi 0.5)) (< alpha pi))
                  (setq
                    p1 (polar pt (+ alpha ( * 0.5 pi)) gap)
                    p2 (polar p1 (+ alpha pi) crnkL)
                  )
                )
                ((and (>= alpha pi) (< alpha (* 0.75 pi)))
                  (setq
                    p1 (polar pt (- alpha ( * 0.5 pi)) gap)
                    p2 (polar p1 (+ alpha pi) crnkL)
                  )
                )
                (T
                  (setq
                    p1 (polar pt (- alpha ( * 0.5 pi)) gap)
                    p2 (polar p1 (+ alpha pi) crnkL)
                  )
                )
              )
              (grdraw pt1 pt 3)
              (grdraw p1 p2 1)
            )
          )
        )
        (redraw)
        (cadr key)
      ))
    )
  )
  (prin1)
))