# How to undo a union later in project and on imported objects

**URL:** <https://discourse.shapr3d.com/t/how-to-undo-a-union-later-in-project-and-on-imported-objects/5267>\
**Category:** Modeling Questions\
**Created:** [July 31, 2019, 9:20am UTC](https://discourse.shapr3d.com/t/how-to-undo-a-union-later-in-project-and-on-imported-objects/5267 "2019-07-31T09:20:00Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![Dhiggs12](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/dhiggs12/32/4189_2.png) [@Dhiggs12](https://discourse.shapr3d.com/u/Dhiggs12)\
**Post date:** [July 31, 2019, 9:20am UTC](https://discourse.shapr3d.com/t/how-to-undo-a-union-later-in-project-and-on-imported-objects/5267/1 "2019-07-31T09:20:00Z")

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How do I undo a union on an object later in the project when I want to edit pieces?

Also, how do I ungroup an imported STL file so I can edit pieces of it. Right now it imports as one grouped object.

Thanks in advance!

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**Author:** ![david.r](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/david.r/32/3991_2.png) [@david.r](https://discourse.shapr3d.com/u/david.r)\
**Post date:** [July 31, 2019, 12:13pm UTC](https://discourse.shapr3d.com/t/how-to-undo-a-union-later-in-project-and-on-imported-objects/5267/2 "2019-07-31T12:13:33Z")

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All the elements have to be at the root of the layers menu, if you have them grouped together when exporting, it will be a unique object impossible to ungroup in the .STL format

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**Author:** ![Dhiggs12](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/dhiggs12/32/4189_2.png) [@Dhiggs12](https://discourse.shapr3d.com/u/Dhiggs12)\
**Post date:** [July 31, 2019, 12:29pm UTC](https://discourse.shapr3d.com/t/how-to-undo-a-union-later-in-project-and-on-imported-objects/5267/3 "2019-07-31T12:29:26Z")

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Right but unless you do a union of objects all connected and then immediately hit the undo arrow, you will be stuck with an object that you can’t ungroup for editing. I figured out after I did a union and later in the project that I need to edit an object that I can’t unless I van undo a union…is there another way besides remaking said object??

Thanks for your time

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**Author:** ![Victor\_Shapr3D](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/victor_shapr3d/32/3502_2.png) [@Victor\_Shapr3D](https://discourse.shapr3d.com/u/Victor_Shapr3D)\
**Post date:** [July 31, 2019, 12:33pm UTC](https://discourse.shapr3d.com/t/how-to-undo-a-union-later-in-project-and-on-imported-objects/5267/5 "2019-07-31T12:33:21Z")

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Also, it’s not possible to undo a union later in the project. We usually recommend that is the last step when done editing the individual model parts. Thank you for your understanding.

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**Author:** ![david.r](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/david.r/32/3991_2.png) [@david.r](https://discourse.shapr3d.com/u/david.r)\
**Post date:** [July 31, 2019, 12:56pm UTC](https://discourse.shapr3d.com/t/how-to-undo-a-union-later-in-project-and-on-imported-objects/5267/6 "2019-07-31T12:56:36Z")

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In this case I don’t know what you could do, I still haven’t found myself in that situation, you could edit the part you need as a single object and then export it, or make the adjustments in shapr3D and export the whole set again.  
not finding myself in that situation I can not help you in more