# Union question

**URL:** <https://discourse.shapr3d.com/t/union-question/35306>\
**Category:** Modeling Questions\
**Created:** [November 24, 2024, 3:36pm UTC](https://discourse.shapr3d.com/t/union-question/35306 "2024-11-24T15:36:38Z")\
**Posts on this page:** 7\
**Page:** 1

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**Author:** ![itguy1024](https://avatars.discourse-cdn.com/v4/letter/i/58f4c7/32.png) [@itguy1024](https://discourse.shapr3d.com/u/itguy1024)\
**Post date:** [November 24, 2024, 3:36pm UTC](https://discourse.shapr3d.com/t/union-question/35306/1 "2024-11-24T15:36:38Z")

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Greetings - why does this gray circle need to be above the orange surface in order for the union function to work? The orange surface has a hole I’m trying to plug and the gray circle should be level with the orange surface. However if they are both level with each other union doesn’t work. Is there a better way to join to shapes?

 ![image](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/3X/5/1/51bb1981b6181a163fff7085dc73bc7fb80e9c2f.jpeg)

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**Author:** ![Oregonerd](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/oregonerd/32/8012_2.png) [@Oregonerd](https://discourse.shapr3d.com/u/Oregonerd)\
**Post date:** [November 24, 2024, 3:50pm UTC](https://discourse.shapr3d.com/t/union-question/35306/2 "2024-11-24T15:50:28Z")

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Well, you can do one of 2 things as work arounds to the Union thing. 1) you can simply select the faces inside the opening to “delete” the hole. 2) you can do the Union and then use the “Replace face” tool to smooth it out. I’m sure they is more but those usually work well enough.

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**Author:** ![itguy1024](https://avatars.discourse-cdn.com/v4/letter/i/58f4c7/32.png) [@itguy1024](https://discourse.shapr3d.com/u/itguy1024)\
**Post date:** [November 25, 2024, 1:27pm UTC](https://discourse.shapr3d.com/t/union-question/35306/3 "2024-11-25T13:27:37Z")

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Unfortunately neither of those will work. This is an imported stl file I’m trying to fix.

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**Author:** ![Oregonerd](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/oregonerd/32/8012_2.png) [@Oregonerd](https://discourse.shapr3d.com/u/Oregonerd)\
**Post date:** [November 25, 2024, 4:03pm UTC](https://discourse.shapr3d.com/t/union-question/35306/4 "2024-11-25T16:03:01Z")

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I suggest a trouble ticket.

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**Author:** ![TheBum](https://avatars.discourse-cdn.com/v4/letter/t/eada6e/32.png) [@TheBum](https://discourse.shapr3d.com/u/TheBum)\
**Post date:** [November 25, 2024, 5:26pm UTC](https://discourse.shapr3d.com/t/union-question/35306/5 "2024-11-25T17:26:45Z")

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You’re probably dealing with issues with curves represented by line segments in the original mesh. Have you tried making the cylinder a larger diameter so that it overlaps the mesh’s hole completely?

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**Author:** ![Oregonerd](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/oregonerd/32/8012_2.png) [@Oregonerd](https://discourse.shapr3d.com/u/Oregonerd)\
**Post date:** [November 25, 2024, 5:28pm UTC](https://discourse.shapr3d.com/t/union-question/35306/6 "2024-11-25T17:28:48Z")

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Or try subtracting from the STL and then union with the same object maybe?

Or try subtracting first then intersect?

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<div class="post-metadata">

**Author:** ![itguy1024](https://avatars.discourse-cdn.com/v4/letter/i/58f4c7/32.png) [@itguy1024](https://discourse.shapr3d.com/u/itguy1024)\
**Post date:** [November 25, 2024, 6:06pm UTC](https://discourse.shapr3d.com/t/union-question/35306/7 "2024-11-25T18:06:00Z")

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I did make the diameter larger previously. Making it 20% bigger allowed me to complete the union.