JOIN command sometimes does not work in autocad

[RSZIHLMAN]

Hello,

This has been happening to me for close to 15 years inconsistently over multiple versions of autocad from early 2000 versions to 2019 over 3 completely different computers.  This has been my standard process in this order:

1. I exploded a drawing 2 times and/or flatten.

2. Change a particular line's layer and/or linetype to ByLayer.

3. Break the line at a point either using the trim command or break command.

4. Then attempt to JOIN the same broken line at some later time.

About half the time the JOIN command does not work. The result is not consistent with multiple lines in the same file or with the exact same line at multiple times in the process. Any help would be greatly appreciated.

Thanks.

[j.palmeL29YX]

A first guess: maybe you work with very large coordinates? 

[Kent1Cooper]

A small example drawing containing some things that you can't Join, but think you should be able to, would help.

A possibility:  What method are you using to "break the line at a point"?  If by two picks, and if for some reason they're not at precisely the same place, that would cause the problem.

Does PEDIT / Join work when JOIN does not?  How about PEDIT / Multiple / Join-with-fuzz-factor?

[RSZIHLMAN]

I would assume no. I do architectural engineering using .25" scale

[RSZIHLMAN]

Example attached. See red line.

What method are you using to "break the line at a point"?  If by two picks, and if for some reason they're not at precisely the same place, that would cause the problem.   Answer: I don't know how to explain any more precisely than I have already stated.

Does PEDIT / Join work when JOIN does not?  How about PEDIT / Multiple / Join-with-fuzz-factor? Answer: My understanding is that PEDIT is for a polyline not a line. If I am wrong please let me know.  

[j.palmeL29YX]

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The red colored objects in your example are two different polylines which do not touch each other at their endpoints. But if you want to join objects they must each other touch at their endpoints. 

What is your goal, what do you want to achieve? (Perhaps the group command can help you?)

(BTW: Before i saw your drawing i was wondering how you were going to break at a point a line using the trim command. Again: the join command - and also pedit/join - need objects with touching/connected endpoints).

[EDIT]: See correction in post #10 please. 

[cadffm]

Hi,

>>"over multiple versions of autocad from early 2000 versions to 2019"
The Join command started in Version2006

>>"Then attempt to JOIN the same broken line at some later time."
JOIN command is for convert two connected (p)lines to one pline,
not to connect to (p)lines include trim or expand action.

>>"or with the exact same line at multiple times in the process."
hmm, there are some function in AutoCAD which working view-dependend,
but Join command isn't one of them.

Thank you for sharing your file, but where is the problem?
You can not mean the both RED lines.. because Join will NEVER join two lines with a gap between.

The only commands which can do this are PEDIT (or MPEDIT).

>>"Answer: I don't know how to explain any more precisely than I have already stated."
Okay, but it doesn't make sense (bcause join will never close a gap)

>>"My understanding is that PEDIT is for a polyline not a line. If I am wrong please let me know."
You are wrong: PEDIT is "for all" objects which are supported to convert to a pline by pedit.

[RSZIHLMAN]

Hello,

My apologies. I tried using the PEDIT command and it was converted to a polyline and I did not check before I saved the file. The 2 red lines are "lines" now. My goal is to JOIN the 2 red lines together so that they become 1 red line as it was before i trimmed them at the pinkish lines. I have been able to perform this exact same task many times, also many times it does not work. Are you saying that me being able to JOIN 2 lines that are not touching is a fluke?

[RSZIHLMAN]

Hello,

Thank you. I thought it was 2006 but couldn't be certain.

Correct. I am using JOIN to connect 2 lines, not to trim or expand

I don't know how that pertains to my questions

I updated the file. I mistakenly converted them to polylines when trying the PEDIT command and did not check before i uploaded the file. The lines are corrected. I do mean the 2 red lines. I have used the JOIN command many times on this exact same situation for over 15 years and the lines do join, about half the time.

JOIN has closed gaps and joined 2 separate lines that were previously 1 line that was broken/trimmed on many

occasions.

Thank you for clarifying, but I have no interest in converting a line into a pline for this scenario.

[j.palmeL29YX]

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@RSZIHLMAN wrote:

Are you saying that me being able to JOIN 2 lines that are not touching is a fluke?

---

No. I said, that it is never possible to join two objects (lines or polylines or arc or splines ...) if they dont touch at their endpoints.

Only one exception: Using the PEDIT/Multiple command you can join objects, if the distance between two endpoints doesn't exceed an fuzzy value (which you're asked for while running the command). Then the command will extend the objects until they touch or add a small additional line to close the gap. The result ever will be an object without any gaps. AutoCAD does not know lines, polylines, arcs, splines with including any gap. (only they can have dashed ... linetypes). 

>> I have been able to perform this exact same task many times<< 

Without any LISP it is not possible to "convert" the two red lines back to one long line (without the gap). If you write you have done this many times with success, please tell us exactly what you do (or how you did it).

[CORRECTION]: 

Also the join command  can join lines if there are gaps between, IF THEY ARE EXACTLY COLLINEAR. If that doesn't work, I guess AutoCAD "thinks" they are not collinear (caused by internal rounding errors or similar?) Then you're right, it is a fluke if it works or not.

[cadffm]

Okay, I have to change my reply, you are right:

😀

1. Yes, the JOIN command CAN close gaps (before I said NO)

2. There is a bug in this Join-command, a 45°/ 135/225/315 angle - math calculation (and precision?) bug

    You should send feedback to AutoDESK (add a link to this Thread)

Simple to reproduce

>>"Correct. I am using JOIN to connect 2 lines, not to trim or expand"

>>"I don't know how that pertains to my questions"

You missunderstand. If there is a gap between both lines (like in your sample),

the Join command have to "extent" one or both line to close the gap,

I wasn't talking about the autocad command trim or extent.

BTW: >>"but I have no interest in converting a line into a pline for this scenario."

LINES -> pedit-join->explode = LINES

[RSZIHLMAN]

Hello,

Well thank you for replying to my question and your time.. Just an FYI. I tried the JOIN command again and I was able to do exactly as I have done many times in the past and this time it worked again. Just so we are perfectly clear. I type in the command "join". I select the 2 lines that i had previously broken with the "trim" command and press 
'enter" and the 2 separate lines became 1 line. If i can figure out a way to record a video file and post it on the forum i will do that so you can see it is definitively possible.

[cadffm]

You're right and we were wrong.

I'm already checking for regularity, but no matter what I find out, only AutoDESK can correct the problem.
Therefore: Send report to AutoDESK.

Mainly it's probably a math/rounding problem, depending
Object data (Coordinates) together with the direction (Angle),
but I also think that this is not everything.
You already mentioned it: It also happens with one and the same (unchanged) object data.

-

Sample: Here is a "copy&paste(to the commandline) Script"

; copyclip he lines to your commandline

_.LINE
_non 50,20
_non 150,20

_.LINE
_non 160,20
_non 200,20

_.LINE
_non 50,20
_non 50,120

_.LINE
_non 50,130
_non 50,170

_.LINE
_non 50,20
_non -50,20

_.LINE
_non -60,20
_non -100,20

_.LINE
_non 50,20
_non 50,-80

_.LINE
_non 50,-90
_non 50,-130

ortho: JOIN will works,

Rotate ALL around 50,20 with 45°

JOIN will works

But recreate the lines and

Rotate ALL around 50,20 with 10° and rotate them again around 50,20 with 35° (10°+35°=45°)

and JOIN will not work

[Kent1Cooper]

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@RSZIHLMAN wrote:

... 3. Break the line at a point ....

---

So that's not really what you're talking about -- that wording implies no gap.

I can't get your red ones to connect using either JOIN or PEDIT / Multiple / Join even with what should be a big-enough fuzz factor, either as Polylines or after Exploding them into Lines.  But if they're Lines [not if they're Polylines], the JL command in JoinLines.lsp, >here<, will do it.

[RSZIHLMAN]

Hello,

Thank you, My apologies. My autocad terminology is severly lacking.

[cadffm]

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@Kent1Cooper  schrieb:

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I can't get your red ones to connect using either

JOIN

works! not at this place/angle, but the gap isn't a general problem.

or PEDIT / Multiple / Join

Works also,

with the join-method extent (or both), but the result isn't one Line (an also not a pline with only 2 vertex)

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[Kent1Cooper]

[I forgot about the Jointype option in PEDIT / Multiple /. Join -- I don't use that command-option combination often enough, typically joining things that meet.]