How to lengthen multiple polylines from multiple midpoints

[Anonymous]

I am trying to change the length of multiple polylines but the midpoint of the polylines needs to stay the same. They are spread out over a large area so doing it manually with the scale command is pretty slow, is there an easier way to do this?

[TheCADnoob]

To better understand the needs of your drawing a screen shot may help. I might check out the EXTEND command in the mean time. Im not sure it will help with the mid point of your need though. 

[Patchy]

Use midpoly?

https://autocadtips1.com/2011/10/21/autolisp-mid-point-of-entire-polyline/

[Kent1Cooper]

If the Scale command is a possibility, I would have to assume these are all [and always and only] one-line-segment Polylines [in which case, is there any reason for them not to be just Lines?].  But whether they are or not, and whether they're Polylines or Lines, LENGTHEN with the DELTA option applied at both ends would do it.  Is that the effect you're after?  If so, a routine could probably be made easily enough that would do that for you to all of a selection set of open-ended Polylines.

[Anonymous]

That sounds like what i'm after. How would i make a lisp that would do that?

[ВeekeeCZ · Accepted solution]

---

@Anonymous wrote:

That sounds like what i'm after. How would i make a lisp that would do that?

---

Try THIS Lee's routine.

HERE is Lee's manual how to usu a LISP.

[Anonymous]

Exactly what I was looking for, thanks!