Help with a lisp routine to add a 12" line to this routine

[Orbytal.edge341183]

;get points to locate centerline of header
         (prompt "\nSelect two points for Rim line: ")
         (command "_.line" pause pause "")
         (setq tmpPnt1 (cdr (assoc 10 (entget (entlast)))))
         (setq tmpPnt2 (cdr (assoc 11 (entget (entlast)))))
         (COMMAND "_.erase" "L" "")
         (setvar "osmode" 0)

         (command "_.line"
                  (polar tmpPnt1 (angle tmpPnt1 tmpPnt2) (* mtScaleFactor 1.25))
                  (polar tmpPnt2 (+ (angle tmpPnt1 tmpPnt2) PI) (* mtScaleFactor 1.25))
                  ""

This part of the lisp draws a line then depending on the dimscale it retracts the 2 ends closer to the center. I was wondering if i could get some help making the lines extend 12" i've tried messing with the scale factors ( IE 1.25 - 1.00 -.25) I seem to be missing something to go in a positive direction versus negative.

Thanks for the help in advance

[pbejse]

retracts the 2 end

or

making the lines extend

which one? or option for both?

[Orbytal.edge341183]

or


which one? or option for both?

Let me explain it a little better......The Lisp draws a line between 2 points and depending on the scale factor (typically dimscale 48 for example) it will stop the line 3" short on either end of the 2 points picked. (for dimscale 96 it will stop 1-1/2" short).

What I am trying to achieve is to extend the line 12" past (at dimscale 4 the 2 points picked. The original "mtscale factor" was set at .0625 for the 3" variable. I adjusted it to 1.25 but it doesnt seem to work. It seems to be referencing the the "actual distance between the 2 points" and messes with the whole line offset. Sometimes it extends too far past the 2 points or stops short by a lot. I hope this explains things a little better. Thanks for the response. I am glad someone is looking

[Bruno.Valsecchi]

Use the midpoint for extent or reduce length

(defun c:LenghtByFact ( / js n dxf_ent dxf_10 dxf_11 mid k dlt_10 dlt_11 nwdxf_10 nwdxf_11)
  (princ "\nSelect lines for reduce or extent length with a factor. ")
  (setq js (ssget '((0 . "LINE"))))
  (cond
    (js
      (initget 3)
      (setq k (getreal "\nGive the factor: "))
      (repeat (setq n (sslength js))
        (setq
          dxf_ent (entget (ssname js (setq n (1- n))))
          dxf_10 (cdr (assoc 10 dxf_ent))
          dxf_11 (cdr (assoc 11 dxf_ent))
          mid
          (mapcar '*
            (mapcar '+ dxf_10 dxf_11)
            '(0.5 0.5 0.5)
          )
          dlt_10 (mapcar '* (mapcar '- dxf_10 mid) (list k k k))
          dlt_11 (mapcar '* (mapcar '- dxf_11 mid) (list k k k))
          nwdxf_10 (mapcar '+ mid dlt_10)
          nwdxf_11 (mapcar '+ mid dlt_11)
          dxf_ent (subst (cons 10 nwdxf_10) (assoc 10 dxf_ent) dxf_ent)
          dxf_ent (subst (cons 11 nwdxf_11) (assoc 11 dxf_ent) dxf_ent)
        )
        (entmod dxf_ent)
      )
    )
  )
  (prin1)
)