Choose between 2 lines before draw it.

[Anonymous]

Hi everyone. Maybe somebody can help me with this Lisp.

The rutine let me picks 2 points and draw 2 posibles plines. Then i choose one and erase.

The lisp works fine, but i dont like that draw the 2 lines and then erase one by choose.

It would be great if after a choosing the 2 points, autocad pre draw both plines and let my choose 

wich of them i want to keep.

Is there a way to do this?

Thanks in advance and regards

Clode

[john.uhden]

I don't understand.  Unless you might be speaking of varying arcs between 2 points, you could have two lines or even polylines but the only difference would be that their start and end points would be reversed.  And one would lie directly on top of the other, so how would you distinguish them?

[Kent1Cooper]

Change the end this way:

….
  (command "pline" a1 i1 a2 ""); from original
  (setq pl1 (entlast))
  (command "pline" a1 i2 a2 ""); from original
  (setq pl2 (entlast))
  (setq keep (car (entsel "\nSelect the one to keep: ")))
  (command "erase" (if (equal pl1 keep) pl2 pl1) "")
  (princ)
)

[That depends on your successfully picking on the right one -- it could be modified to ask again if you miss.]

[Anonymous]

Hi John, and thanks for the replay.

Sorry about my mistake in the explanation

The 2 polylines have 2 segments and 3 vertexs (thats why i attached the lsp, to see this) then there are only

two polylines (2 segments, 3 vertex and 45 grads between segments) that connect the two point.

Thanks again for your time.

Clode

[Anonymous]

---

@Kent1Cooper  ha escrito:

Change the end this way:

….
  (command "pline" a1 i1 a2 ""); from original  (setq pl1 (entlast))  (command "pline" a1 i2 a2 ""); from original  (setq pl2 (entlast))
  (setq keep (car (entsel "\nSelect the one to keep: ")))
  (command "erase" (if (equal pl1 keep) pl2 pl1) "")
  (princ)
)

[That depends on your successfully picking on the right one -- it could be modified to ask again if you miss.]

---

Hi Kent, thanks by the replay.

Your idea works fine, but the lisp still draw the 2 polys and then deleted one. im trying that

lisp looks more profesional. It means that i looking a way to preview one or the other poly

by example alternating since i move the mouse and when i click appears the last i see it.

Sorry but me english, i hope you understand my

Thanks.

Clode

[Anonymous]

I am confused are you trying to join 1 end ? if so then it can be done pretty easy. 1 line.

[john.uhden]

I don't know what it's for, but I rather like your code.

I think the only way to avoid the choice is for you to write a list of properties or conditions or relationships that you have in your head to make a choice.

[john.uhden]

Maybe now I get it... You want to pick the one to keep, not the one to erase.

(command "pline" a1 i1 a2 "")
(setq ss (ssadd (entlast)))
(command "pline" a1 i2 a2 "")
(ssadd (entlast) ss)
(setq e (car (entsel "\nSelect the pline to keep: ")))
(command "erase" (ssdel e ss) "")
(princ)

[Anonymous]

I attach an image of the 2 posible polys from 2 points.
There are the 2 posibles línes from where o want to choose beforw draw it.

Clode

Clode

[john.uhden]

I guess I still don't understand how you can make a choice when there is nothing yet to choose from, unless there are characteristics that you can define to apply to the choice.

[Anonymous]

John, of you can see the image I attach you Will see the 2 options.
Anyway, giving 2 points, There are 2 ways to make a polyline of 2 segments and 45 degrees in between them that join booths points. This is the choice.

Regards

[Kent1Cooper]

---

@Anonymous wrote:

.... i looking a way to preview one or the other poly

by example alternating since i move the mouse and when i click appears the last i see it.

….

---

That can be done using (grread) and a temporary (entmakex), as in the attached PP.lsp file.  It does not yet include things like error handling, but it seems to work in limited testing.

The way it decides which one to show as you move the mouse is by which of the two possible middle-vertex locations is closer to the mouse location. It could probably be altered to choose by which side of the end-to-end line the mouse is on, if that would be better.

[john.uhden]

Your wizardry is very cute.  I like that kind of inventiveness.

Gotta get that *error* function in there, though.

[john.uhden]

I was just thinking that a slightly better way might be to entmakex both of them (e1 and e2) just once but then alternately entdel one or the other depending on the cursor location.  For you lurkers, the entdel function can be used to delete and to undelete an object by its entity name.

[Anonymous]

---

@Kent1Cooper  ha escrito:

---

@Anonymous wrote:

.... i looking a way to preview one or the other poly

by example alternating since i move the mouse and when i click appears the last i see it.

….

---

That can be done using (grread) and a temporary (entmakex), as in the attached PP.lsp file.  It does not yet include things like error handling, but it seems to work in limited testing.

The way it decides which one to show as you move the mouse is by which of the two possible middle-vertex locations is closer to the mouse location. It could probably be altered to choose by which side of the end-to-end line the mouse is on, if that would be better.

---

Hi Kent, and thanks for the replay.

Yes I think the solution goes that way. I will check your lsp soon and then tell you about it.

Thanks again and regards.

Clode

[john.uhden]

I think what @Kent1Cooper did is very clever, but I think it worked more
easily with showing both and picking which one to keep. I mean easier for
the user too.
Once again, though, if there were rules that would dictate which one was
desired over the other, then there would be no need for a user's choice,
which allows for a 50% failure rate.

[Anonymous]

John, the decission of the election depends of the design of other parte of geometry that Who is drawing must make a choice.
Anyway, that you say that shows the 2 options and pick is not a bad idea.

Thanks!!

[Kent1Cooper]

---

@Kent1Cooper wrote:

That can be done using (grread) and a temporary (entmakex), as in the attached PP.lsp file.  ....

---

Here's an enhanced version that shows you both Polylines at all times, "featuring" the one that will remain if you pick.  It still chooses which to feature based on distance to the "shoulders" rather than on which side of the center-line the cursor is, but that could be changed.  If you use a white background [I use black], consider changing the 252's to 254's or some other pale color, possibly some other-than-grey variety.