Boundary creation - A closed boundary could not be determined

[darawork]

Hi,

This is a very common problem when I use Autocad, since as long as I can remember.
Selecting inside a closed loop Polyline to generate a boundary consistantly throws up this error.
Although, after fencing off increasingly small areas, the user can convince Autocad that this is not in fact impossible.

Why is it that this consistantly happens, please be as technical as possible if needed.
The closed polyline does not have any self-intersecting angles or sections.
It is flat to the Z axis. There are no holes or missing segments.
My drawing file is set to Decimal, with a 0.0000 precision readout.
Limits are set to be OFF.
Polyline is centered on the origin point (0,0,0).
XY plane is parallel to the UCS.
Overkill command ran with no deletions.
HPGAPTOL: 0.000

This has always infuriated me with AutoCad. It is of my opinion that the boundary creation routine code needs a good seeing to. Even Microsoft Paints 'Paint Bucket' tool seems to be far superior and infinitely quicker.

If indeed there is a problem with my closed Polyline loop, which there isn't, AutoCad could at least prompt to fix it automatically.

I tried to post this into the AutoCad Ideas board, but there doesn't seem to be one.

Regards 🙂

[paullimapa]

I also noticed that when the boundary shape becomes too complex AutoCAD cannot even return an area. The only way to get around that is to divide the boundary into different smaller areas to reduce complexity

Ive also in the past when using say BPoly command specify the objects I want AutoCAD to use to search for the boundary. So I would help it along by selecting my predrawn boundary then pick point inside that and usually AutoCAD will return with its own drawn boundary object on top of mine. Sometimes when it’s too complex it’ll create a Region instead of a Pline boundary. 

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[pendean]

When you encounter that problem, it is best if you try using MPEDIT command (or BOUNDARY command) to create/recreate a closed PLINE of the may objects, then ZOOM so that only that outline is on screen (nothing else), AND don't forget to opt for the "select boundary" instead of "pick point" during the HATCH command.

FWIW having a busy screen like in your screenshot and opting or "pick point" is just asking for this old problem to always rear its ugly head over and over again.

HTH

[ВeekeeCZ]

It would be interesting to investigate your drawing... can you post this dwg?

[darawork]

Hi,

Pendean, thanks for the reply. Yup, I just exploded the closed polyline loop, then used Mpedit to Join (0.000 Fuzz) then CLosed it. Same problem when trying to create a boundary with the BOUNDARY command. Btw I couldn't see the option to select a Polyline rather than an internal pick point. I tried to create a Region too, still no luck. That usually works.
.... And my screen is not busy, hehe, Standard AutoCad toolbar hehehe. If it's messy looking, Autodesk made it that way.

Thanks for the other replies guys.

Here is the file if anyone wants to take a look at it (AutoCad 2022):


Regards,

[ВeekeeCZ]

Why do you hatch it by picking a point? You can use "Select object" option, select pline and hatch that without issues.

Edit. Reading now that you probably found it. So solved I guess.

[darawork]

Hi,

I want to EXTrude this shape. It is the main outline, there are a lot of other shapes inside this on the original drawing that I want to subtract from it... eventually. :edit: Still not solved.

As I mentioned above, I fully suspect that this is a limitation of the program that has been swept under the carpet for years. Be it floating point maths, a very unoptimised routine, or just a gremin in the code that keeps evading dectection.

Every thread where I've searched for "a closed boundary could not be determined" results in the same general outcome; somebody admitting that it is an AutoCad problem, however subtly. Even in the replies above. Even the help file is worded in such a way so as to skoot 'around' the problem without actually admitting blame.

Regards 🙂

[ВeekeeCZ · Accepted solution]

HERE is the selfintersect routine that could help to locate the issues... 

[pendean]

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@darawork wrote:

.... And my screen is not busy, hehe, Standard AutoCad toolbar hehehe. If it's messy looking, Autodesk made it that way.

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No, I meant all of this is always included when AutoCAD creates a hatch they way you are doing it, a big mistake: you need to remove that from access all the time, only the complete outline of what you need to hatch should always be visible when using the ill-chosen PICK POINTS option (best used for simple shapes only).

I see others found additional imperfections with your outline, hope that helps too.: HATCH command is very unforgiving.

[darawork]

Hi,

Thanks for linking that AutoLISP routine. I use it in work, but I'm at home today.
I just zoomed in to trim the loop, and Autocad is now frozen. I'm admitting defeat for the day.

As it stands, the BOUNDARY command should still manage to draw a containment around the perimeter of this self-intersecting loop, and not just throw its toys out of the pram.

Pendean, ahh, get you now. That copy with the messy lines going through it was just for illustration purposes only. It shows what is needed to be done so as AutoCad can manage to create the boundary in bite sized chunks. The file I attached above only has one shape file inside it. Btw, I'm trying to extrude, through the process of boundary creation first, not Hatch.. but I suspect that they use the same code to some extent.

Regards,

[paullimapa]

after applying @ВeekeeCZ fix on the complex Pline, at least now I can REGION it & EXTRUDE it.

of course with Hatch I always use select object and not pick point

[dany_rochefort]

@darawork   Here is your extruded lamp!  No lisp, boundary command, region or hatch required... 

Once you've got your shape, run the overkill command on it. It will clean it up and expose non connected segments. Connect all those non connected segments using Fillet command. Try to extrude your closed polyine from there (non need to perform boundary command) If it doesnt work, run Overkill on your shape AGAIN and re-re-connect everything. Then try to exturde. Repeat as many times as necessary.

First time i ran overkill on this i got 923 segments deleted. Tried to extruded after fillet but i couldnt. Had to run it a second time which deleted 18 other segement.  Once everything was Filleted back together i was able to extrude your beautiful lamp shape. 

[darawork]

• Windows 3.11 had a Bucket Fill tool in MSpaint, long before Photoshop or Industrial Light and Magic even existed. Years later, we're still having to put up with "a Closed boundary could not be determined". Computer says No? 
• 🔐

[dany_rochefort]

@darawork You question was answered, a closed boundary could be determined afterall and there a a few different options to choose from. 

Kindly accept as solutions for all those posts that were able to sucessfully extrude your lamp.  We did afterall take the time to look into your problem, find a solution and reply back. 

Best Regards, 

[carlusremod]

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