Union issue

Union issue

Anonymous
Not applicable
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15 Replies
Message 1 of 16

Union issue

Anonymous
Not applicable

Hi there. Im relatively new to using autocad as ive only just learnt the basics with this free trial.

I've always used union to join together solids and the seperating lines always disappeared between objects. This time however there is a line that will not disappear between two objects that I have unioned.

I have attached a picture showing the line that i cant seem to get rid of.

 

Thanks

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4,553 Views
15 Replies
Replies (15)
Message 2 of 16

imadHabash
Mentor
Mentor

Hi, 

 

I suggest to use Solidedit (Clean) command and choose solid options (Face/Edge/Body)

 

Command: SOLIDEDIT
Solids editing automatic checking: SOLIDCHECK=1
Enter a solids editing option [Face/Edge/Body/Undo/eXit] <eXit>: b
Enter a body editing option
[Imprint/seParate solids/Shell/cLean/Check/Undo/eXit] <eXit>:

 

or you can reach it from ribbon as attached image

 

cl.png

 

Good Luck..

 

 

Imad Habash

EESignature

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Message 3 of 16

Kent1Cooper
Consultant
Consultant

Welcome to these Forums!

 

I would assume that the two pieces did not align exactly, but had some slight offset in plane, or perhaps did not meet exactly, but had a tiny gap between them.  It's hard to say without either Zooming in much closer or if you can post the "before" drawing file [even just the two pieces, without all the other stuff].

Kent Cooper, AIA
Message 4 of 16

eduardovbonfim
Observer
Observer

Hi this solution didn´t work for me, still , im having issues with a redundant line in my solid, i´ve tried to push and pull or to subtract the area and union again, but none of those worked. 

 

Its attached a image of my solid

 

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Message 5 of 16

neaton
Advisor
Advisor

Did you try @imadHabash and @Kent1Cooper suggestions? Can you post your dwg file? An image file doesn't help much in this situation.

Nancy


@eduardovbonfim wrote:

Hi this solution didn´t work for me, still , im having issues with a redundant line in my solid, i´ve tried to push and pull or to subtract the area and union again, but none of those worked. 

 

Its attached a image of my solid

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Message 6 of 16

eduardovbonfim
Observer
Observer

Hi, yes i´ve tryed but none of them worked for me, but i found a solution myself, by creating a mold of the 3d using subtract function, and them creating a new 3d using the mold i made before, so the redudant line has gone.

 

Thanks!

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Message 7 of 16

Anonymous
Not applicable

If Union has worked every other time, then something is different this time.

If lines exist then you know the solids are either misaligned or the dimensions of the solids are not truly equal. While alignment is easy to verify, dimensions are more subtle in that they may report as being the same but may actually be different by a small amount.  Take care that when you create the solids, they have the same dimensions. 

The "SLICE" command can be used to get rid of the lines. 

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Message 8 of 16

wpotgieter
Explorer
Explorer

AutoCAD 3d definitly have a issue with the joining lines, I have the same problem sometimes and it doesnt matter how well I align my ucs.

 

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Message 9 of 16

Alfred.NESWADBA
Consultant
Consultant

Hi,

 

>> AutoCAD 3d definitly have a issue with the joining lines

Please upload your drawing with the 2 lines not joining so we can see where AutoCAD has issues.

 

- alfred -

------------------------------------------------------------------------------------
Alfred NESWADBA
ISH-Solutions GmbH / Ingenieur Studio HOLLAUS
www.ish-solutions.at ... blog.ish-solutions.at ... LinkedIn ... CDay 2026
------------------------------------------------------------------------------------

(not an Autodesk consultant)
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Message 10 of 16

wpotgieter
Explorer
Explorer

Its on the Magenta part.

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Message 11 of 16

Alfred.NESWADBA
Consultant
Consultant

Hi,

 

>> Its on the Magenta part

No file to look into...

 

- alfred -

------------------------------------------------------------------------------------
Alfred NESWADBA
ISH-Solutions GmbH / Ingenieur Studio HOLLAUS
www.ish-solutions.at ... blog.ish-solutions.at ... LinkedIn ... CDay 2026
------------------------------------------------------------------------------------

(not an Autodesk consultant)
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Message 12 of 16

wpotgieter
Explorer
Explorer

It's on the magenta part

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Message 13 of 16

Alfred.NESWADBA
Consultant
Consultant

Hi,

 

you mentioned "joining lines has issues" ... your drawing only contains one line (other object types exist, but no second line to be used to join 2 lines). So which 2 lines do you try to join?

 

Important for your drawing general: Your coordinates are outside any valid coordinate system, as you can see here:

 

20220131_113531.png

 

Moving your geometry more close to 0,0,0 would result in

  • more accurate display
  • more accurate calculations (line object snap, intersection points, offset objects ...)
  • valid for beeing on earth (if these should be geographic coordinates)

 

- alfred -

------------------------------------------------------------------------------------
Alfred NESWADBA
ISH-Solutions GmbH / Ingenieur Studio HOLLAUS
www.ish-solutions.at ... blog.ish-solutions.at ... LinkedIn ... CDay 2026
------------------------------------------------------------------------------------

(not an Autodesk consultant)
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Message 14 of 16

wpotgieter
Explorer
Explorer

wpotgieter_0-1643628509077.png

I joined this part of a head wall to the rest. The press/pull function refused to work also the normal Extrude so I ended up lofting it. It did join but the joint line remain.

 

I traced it from a coordinated scan so I wanted to keep the position so that I can insert it to coordinates in my layout drawing.

 

Thanks for your concern.

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Message 15 of 16

Alfred.NESWADBA
Consultant
Consultant

Hi,

 

>> I traced it from a coordinated scan so I wanted to

>> keep the position

Then store a line inside your dwg on a frozen layer, from the center of your geometry to the origin (0,0,0). This gives you the chance to move it back after your work.

To the coordinates, not sure why your scanner returns values like Y = -3.25*10^9 Millimeter, for me that does not make sense, but shown the way above you could save this vector.

 

>> The press/pull function refused to work also

Please try with normal coordinates again.

 

>> It did join but the joint line remain

"it did join" ... are you referring to command _UNION or command _JOIN? Because 3D-Solids can't be joined).

If you speak about command _UNION, then sorry, command _UNION has nothing to do with lines, it does not create lines and so a line could not remain if you have not created it.

 

So back to .. what do I understand wrong about "AutoCAD 3d definitly have a issue with the joining lines"?

 

- alfred -

------------------------------------------------------------------------------------
Alfred NESWADBA
ISH-Solutions GmbH / Ingenieur Studio HOLLAUS
www.ish-solutions.at ... blog.ish-solutions.at ... LinkedIn ... CDay 2026
------------------------------------------------------------------------------------

(not an Autodesk consultant)
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Message 16 of 16

Alfred.NESWADBA
Consultant
Consultant

Additional information ... Moved all parts close to 0,0,0 ... run command _UNION and was able to union all existing 3D-Solids (if that was the question).

 

- alfred -

------------------------------------------------------------------------------------
Alfred NESWADBA
ISH-Solutions GmbH / Ingenieur Studio HOLLAUS
www.ish-solutions.at ... blog.ish-solutions.at ... LinkedIn ... CDay 2026
------------------------------------------------------------------------------------

(not an Autodesk consultant)
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