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@faridfarmani2000 wrote:
Hey, Gordon. What if we have a polyline?
May not be watching after all these years, so....
If you want to get the start and end points of a Polyline from the entity data list [if in a 'data' variable as in previous posts], all vertices are in (assoc 10) entries. You could do this:
(setq start (cdr (assoc 10 data))); same as for a Line
But for the end:
(setq end (cdr (assoc 10 (reverse data)))); the last such entry
BUT if it's a closed Polyline, that will get the last vertex, not the end [which is at the same place as the start].
The other way, not involving the entity-data list [with LNAME being the entity name as in earlier posts]:
(setq
start (vlax-curve-getStartPoint LNAME)
end (vlax-curve-getEndPoint LNAME)
)
which will give you the actual end [back at the beginning] for a closed one, rather than the last vertex. You may need to run:
(vl-load-com)
to be able to use those functions.
Kent Cooper, AIA 
@Kent1Cooper wrote:
....
The other way...:
(setqstart (vlax-curve-getStartPoint LNAME)
end (vlax-curve-getEndPoint LNAME)
)
....
And by the way, that's a universal approach, and will get the start and end points from anything that has them -- not just a Line or Polyline, but an Arc, Circle, Ellipse, or Spline, and also the start point [only] of a Ray.
Kent Cooper, AIA
@erik.vold wrote:
What would I do if I wanted to make a lisp that changed the start and end points of a line?
There are several ways. Do you have the points defined/saved already somehow, or do you need to ask the User for them, or....? Also, since Message 1 talks in terms of a Line but the snippet of entity data shown is clearly about a Polyline, which are you actually asking about? [It would make a big difference to some of the alternative ways.]
Kent Cooper, AIA
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