Find midpoint of a line

[delta]

Hi

I have used Autolisp to insert a line.

(setq p1 (getpoint  "\nPick top hole on LH Staunchon:"))

(setq p2 (getpoint  "\nPick top hole on RH Staunchon:"))

(command "pline" p1 p2 "")

(setq topline (entlast)

Using Lisp I would like to get the mid point of "topline" so I can insert a block at that point.

Can you help me with this please?

 

Regards Tony

[marko_ribar]

(defun midp ( p1 p2 )

  (mapcar (function (lambda ( a b ) (/ (+ a b) 2.0))) p1 p2)

)

[BIGAL]

Another

(setq mp (mapcar '* (mapcar '+ p1 p2) '(0.5 0.5)))
or
(setq mp (mapcar '/ (mapcar '+ p1 p2) 2.0))

 

[Lee Mac]

2 minutes ago, BIGAL said:

Another

(setq mp (mapcar '/ (mapcar '+ p1 p2) 2.0))

 

 

This will not work - a lambda is required or '(2.0 2.0 2.0)

[Lee Mac]

Another alternative is use polar, e.g.:

(polar p1 (angle p1 p2) (/ (distance p1 p2) 2.0))

 

Edited Saturday at 10:22 PM by Lee Mac

[BIGAL]

OOPS, thanks Lee. Forgot it uses divide X, Y & Z, not the actual point. I think "Cal" has a midpoint function as well.

 

Edited Saturday at 10:27 PM by BIGAL

[delta]

Thank you all very much for your input. That part is now working perfectly.

I have another question. I hope I'm not over staying my welcome.

 

Please see the attachment

Sample Object 2.pdf

[BIGAL]

Does it have to use a Block ? For me just enter the sizes and pick pt1. Then just draw the objects. If the pdf is just showing a rectang as the block rather than a true object then why cant you put the X scale for the block. Re starting at 75 up to 1400 can use something like this.

 

Need the vertical size of the rectang. What is the gap to the block.

 

 

 

So if you have blocks that are not a rectang what is there names like 275rec etc ?

 

The best thing here is post a real dwg I am sure can be automated.