# Union fails on Mirrored bodies

**URL:** <https://discourse.shapr3d.com/t/union-fails-on-mirrored-bodies/29945>\
**Category:** Modeling Questions\
**Created:** [January 20, 2024, 4:25pm UTC](https://discourse.shapr3d.com/t/union-fails-on-mirrored-bodies/29945 "2024-01-20T16:25:04Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![flarecz](https://avatars.discourse-cdn.com/v4/letter/f/e36b37/32.png) [@flarecz](https://discourse.shapr3d.com/u/flarecz)\
**Post date:** [January 20, 2024, 4:25pm UTC](https://discourse.shapr3d.com/t/union-fails-on-mirrored-bodies/29945/1 "2024-01-20T16:25:04Z")

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Hi, I am using the beta version on IPad. Once you split a body, the delete one part and Mirror the other part, the Union command of those mirrored bodies fails. It claims “the boolean operation failed”. Any hint or a beta bug? Thanks.

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**Author:** ![Bob3DPO](https://avatars.discourse-cdn.com/v4/letter/b/7993a0/32.png) [@Bob3DPO](https://discourse.shapr3d.com/u/Bob3DPO)\
**Post date:** [January 20, 2024, 4:42pm UTC](https://discourse.shapr3d.com/t/union-fails-on-mirrored-bodies/29945/2 "2024-01-20T16:42:49Z")

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Hi @flarecz ,  
My guess is that if it did union, you’d get a non-manifold body, and Shapr3d won’t do that. This type of failed Boolean is not because of mirror then delete, but due to the geometries of the two bodies. Can you attach a screenshot?

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**Author:** ![flarecz](https://avatars.discourse-cdn.com/v4/letter/f/e36b37/32.png) [@flarecz](https://discourse.shapr3d.com/u/flarecz)\
**Post date:** [January 20, 2024, 6:27pm UTC](https://discourse.shapr3d.com/t/union-fails-on-mirrored-bodies/29945/3 "2024-01-20T18:27:02Z")

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![IMG_0032](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/3X/9/5/9527d36d33bf3c02d227b5727066290aaae78f93.jpeg)

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**Author:** ![flarecz](https://avatars.discourse-cdn.com/v4/letter/f/e36b37/32.png) [@flarecz](https://discourse.shapr3d.com/u/flarecz)\
**Post date:** [January 20, 2024, 6:35pm UTC](https://discourse.shapr3d.com/t/union-fails-on-mirrored-bodies/29945/4 "2024-01-20T18:35:40Z")

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Screenshots attached.

The left part is the one I cut, the right is mirrored.

 ![IMG_0033](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/3X/1/b/1bf4e5feb7fffe248bf0e0cbd920dd97256cab69.jpeg)

I found out that if I move the right part (mirrored) by 0.01mm to the left, than the Union works properly.

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**Author:** ![Bob3DPO](https://avatars.discourse-cdn.com/v4/letter/b/7993a0/32.png) [@Bob3DPO](https://discourse.shapr3d.com/u/Bob3DPO)\
**Post date:** [January 20, 2024, 6:42pm UTC](https://discourse.shapr3d.com/t/union-fails-on-mirrored-bodies/29945/5 "2024-01-20T18:42:10Z")

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I suspect the error has to do with the spot circled. If you were to remove that fillet before your split and mirror, you may not have to shift one piece. That said, shifting a piece a small amount will often correct this type of Boolean failure.

 ![IMG_0494](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/3X/b/a/ba6f9af7c39d77e68b7f6f9421ba19ff5f762699.jpeg)

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**Author:** ![flarecz](https://avatars.discourse-cdn.com/v4/letter/f/e36b37/32.png) [@flarecz](https://discourse.shapr3d.com/u/flarecz)\
**Post date:** [January 20, 2024, 6:59pm UTC](https://discourse.shapr3d.com/t/union-fails-on-mirrored-bodies/29945/6 "2024-01-20T18:59:13Z")

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Thank you very much for your feedback, really appreciated!