Hi,
>> I want to make a (poly)line a cetrain lenght, while its already placed on the right position. <<
it will be great if we have an image that describe your issue because there are many tricks that we can follow depending on the issue? BUT i can give you an idea that it may help from using Parametric (Fix option ) .
Imad Habash
HELLO,
Do you mean extend to both sides. A Lisp may do your job
2 sides extended by 10mm.
DEX > Specify length > Choose objects.
Double Extend Lisp
Command DEX From Lee Mac:
http://www.lee-mac.com/doubleextend.html
Cheers,
Vinay Vijayakumaran 
Hi,
for this steel bars i usually draw a circle from the mid point with proper needed diameter .
Imad Habash
If they're always straight things as in your images [whether Lines or Polylines of any variety or Blocks or...], you can use SCALE, give it the midpoint as the base, and use the Reference option -- pick the ends for the Reference length, and give it the desired total length. A routine could probably be written to automate that for you.
EDIT: By the way, this has come up before. Some Searching will likely find other solutions, too.
Something like this may work
@jeroendewind wrote:
.......
But also sometimes I want to make a (poly)line a cetrain lenght, while its already placed on the right position.
Thanks
;:Ranjit Singh
;;9/1/17
(defun c:somefunc (/ adoc del ss1 tot)
(vla-startundomark (setq adoc (vla-get-activedocument (vlax-get-acad-object))))
(setq ss1 (ssget '((0 . "line,lwpolyline"))))
(and ss1
(setq tot (getdist "\nSpecify total length: "))
(mapcar '(lambda (x)
(setq del (/ (- tot (getpropertyvalue x "Length")) 2.0))
(command-s "._lengthen"
(vlax-curve-getstartpoint x)
"_delta"
del
(vlax-curve-getstartpoint x)
(vlax-curve-getendpoint x)
""))
(vl-remove-if 'listp (mapcar 'cadr (ssnamex ss1)))))
(vla-endundomark (setq adoc (vla-get-activedocument (vlax-get-acad-object)))))
One thing I would worry about with using Lengthen and its Delta option, and having the routine pick the ends, is that it might sometimes "see" some other object.
Here's my take on it, for Lines and single-line-segment LWPolylines only. It uses Scale, and if the object is a Polyline, it re-assigns its original global width to undo the changing of that in the Scale command.
(vl-load-com)
(defun C:TLM ; = Total Length with Midpoint kept in place
(/ tl ent etype wid obj)
(if
(and
(setq tl (getdist "\nTotal Length desired: "))
(setq ent (car (entsel "\nSelect Line or single-line-segment Polyline: ")))
(wcmatch (setq etype (cdr (assoc 0 (setq edata (entget ent))))) "LINE,LWPOLYLINE")
(or
(= etype "LINE")
(and
(not (vlax-curve-isClosed ent))
(= (vlax-curve-getEndParam ent) 1.0); single-segment
(member '(42 . 0.0) edata); line segment [not arc]
(setq wid (cdr (assoc 43 edata))); constant width
); and
); or
); and
(progn ; then
(command ; then
"_.scale" ent "" "_none"
(mapcar '/ (mapcar '+ (vlax-curve-getStartPoint ent) (vlax-curve-getEndPoint ent)) '(2 2 2))
(/ tl (vla-get-Length (setq obj (vlax-ename->vla-object ent)))); new length
); command
(if (= etype "LWPOLYLINE") (vla-put-ConstantWidth obj wid)); restore original width
); progn
); if
(princ)
); defun
It could be made to allow multiple selection, to work with other-than-LW Polylines, to notify you if you picked the wrong kind of thing or missed, remember your last length and offer it as default the next time, etc., and of course could use *error* handling and all that stuff.
@Kent1Cooper wrote:
One thing I would worry about with using Lengthen and its Delta option, and having the routine pick the ends, is that it might sometimes "see" some other object.
@Kent1Cooper, the advantage of lengthen as opposed to scale is that it will work with straight as well as angular polylines and even when it has arcs. But you bring up a good point. That is an inherent flaw in "LENGTHEN". Even after you select the object it will "see" other objects at the selection point. One work around is to isolate the object. This, however, could be very memory intensive depending on the drawing. Anyways, here it is
;:Ranjit Singh
;;9/1/17
(defun c:somefunc (/ adoc del ss1 tot)
(vla-startundomark (setq adoc (vla-get-activedocument (vlax-get-acad-object))))
(setq ss1 (ssget '((0 . "line,lwpolyline"))))
(and ss1
(setq tot (getdist "\nSpecify total length: "))
(mapcar '(lambda (x)
(command-s "._isolateobjects" x "")
(setq del (/ (- tot (getpropertyvalue x "Length")) 2.0))
(command-s "._lengthen" x "_delta" del (vlax-curve-getstartpoint x) (vlax-curve-getendpoint x) "")
(command-s "._unisolateobjects"))
(vl-remove-if 'listp (mapcar 'cadr (ssnamex ss1)))))
(vla-endundomark (setq adoc (vla-get-activedocument (vlax-get-acad-object)))))
@MikeKovacik4928 wrote:
Your lisp doesn't seem to work for me.
I load it, I get the above error message.Command: APPLOAD
TLM.lsp successfully loaded.
Command: ; error: malformed list on input.....
As attached, that's all one line of code. It can't be that way -- the semicolon near the beginning "comments out" everything that follows it until a new line starts for the operational content. That new line never starts, it never gets to the closing right parenthesis for the (defun) function which is therefore never completed [that would be the cause of the "malformed list" error], and there's no definition.
