# Non-manifold detection

**URL:** <https://discourse.shapr3d.com/t/non-manifold-detection/13612>\
**Category:** Modeling Questions\
**Created:** [June 30, 2021, 4:48am UTC](https://discourse.shapr3d.com/t/non-manifold-detection/13612 "2021-06-30T04:48:53Z")\
**Posts on this page:** 13\
**Page:** 1

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**Author:** ![NathanD](https://avatars.discourse-cdn.com/v4/letter/n/dec6dc/32.png) [@NathanD](https://discourse.shapr3d.com/u/NathanD)\
**Post date:** [June 30, 2021, 4:48am UTC](https://discourse.shapr3d.com/t/non-manifold-detection/13612/1 "2021-06-30T04:48:53Z")

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I’ve created a model that I was getting ready to 3D print.  
I’m getting a warning ⚠ in the slicer software (Lychee) that the STL is non-manifold, and I cannot find what might be causing the error in the original model created in Shapr3d.

I know that if you are in the process of modeling a feature in Shapr that is non-manifold, it will give you an error message. I don’t recall that happening though.

Is there any tips or tricks to find non-manifold geometry?

Thanks.

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**Author:** ![TigerMike](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/tigermike/32/32650_2.png) [@TigerMike](https://discourse.shapr3d.com/u/TigerMike)\
**Post date:** [June 30, 2021, 5:32am UTC](https://discourse.shapr3d.com/t/non-manifold-detection/13612/2 "2021-06-30T05:32:53Z")

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For starters, is the body you exported one solid body? Meaning, it not composed of more than one body that have yet to be **UNIONED** as one.

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**Author:** ![NathanD](https://avatars.discourse-cdn.com/v4/letter/n/dec6dc/32.png) [@NathanD](https://discourse.shapr3d.com/u/NathanD)\
**Post date:** [June 30, 2021, 7:04am UTC](https://discourse.shapr3d.com/t/non-manifold-detection/13612/3 "2021-06-30T07:04:23Z")

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@TigerMike yes, I did verify that it is one body.  
A couple days ago it wasn’t because I did not know it would be an issue, so I tried it as one complete union, still no luck.

Part in question.

 ![IMG_0490.PNG](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/2X/c/cc37ff2bddc870db9ee5f3d38929d5d9d48bac8d.jpeg)

 ![IMG_0491.PNG](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/2X/0/0404f3f9b7388d2be4050f72b7402935c7521e21.jpeg)

 ![IMG_0492.PNG](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/2X/6/6adac1106efd4ccd01d8c2d0a8b35e4dc6401b12.jpeg)

![A1F7BF15-3391-41B8-8DF9-E4B8B1B8D5BF_4_5005_c](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/2X/3/390860f17e90ddda9ccaa43e17877ca71bb7742f.jpeg)

Thanks

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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:** [June 30, 2021, 2:11pm UTC](https://discourse.shapr3d.com/t/non-manifold-detection/13612/4 "2021-06-30T14:11:55Z")

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You moved the body and there is nothing else that exists in that space? Try making it transparent and look for internal anomalies?

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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:** [June 30, 2021, 2:23pm UTC](https://discourse.shapr3d.com/t/non-manifold-detection/13612/5 "2021-06-30T14:23:09Z")

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Try splitting objects/parts in Lychee and see if something reveals itself.

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<div class="post-metadata">

**Author:** ![NathanD](https://avatars.discourse-cdn.com/v4/letter/n/dec6dc/32.png) [@NathanD](https://discourse.shapr3d.com/u/NathanD)\
**Post date:** [June 30, 2021, 9:10pm UTC](https://discourse.shapr3d.com/t/non-manifold-detection/13612/6 "2021-06-30T21:10:08Z")

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@Oregonerd I guess I can split the part into multiple pieces, import them individually into Lychee and see what body has the problem.

And yes, there are no other bodies.

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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:** [June 30, 2021, 11:55pm UTC](https://discourse.shapr3d.com/t/non-manifold-detection/13612/7 "2021-06-30T23:55:31Z")

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A good tool for checking manifold issues is MeshMixer. It has an analysis mode where it will identify non-manifold and other issues.

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**Author:** ![NathanD](https://avatars.discourse-cdn.com/v4/letter/n/dec6dc/32.png) [@NathanD](https://discourse.shapr3d.com/u/NathanD)\
**Post date:** [July 1, 2021, 3:13am UTC](https://discourse.shapr3d.com/t/non-manifold-detection/13612/8 "2021-07-01T03:13:12Z")

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@TheBum thanks, I’ll give that a shot.

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**Author:** ![NathanD](https://avatars.discourse-cdn.com/v4/letter/n/dec6dc/32.png) [@NathanD](https://discourse.shapr3d.com/u/NathanD)\
**Post date:** [July 1, 2021, 4:56pm UTC](https://discourse.shapr3d.com/t/non-manifold-detection/13612/9 "2021-07-01T16:56:52Z")

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@TheBum It totally worked great, thanks!

Turns out there was a surface non-manifold issue AND a hole issue, that I NEVER would have found.

One click and both were fixed. I imported them into the slicer and the errors are gone 👍 👍 👍

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**Author:** ![Istvan](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/istvan/32/23668_2.png) [@Istvan](https://discourse.shapr3d.com/u/Istvan)\
**Post date:** [July 1, 2021, 6:11pm UTC](https://discourse.shapr3d.com/t/non-manifold-detection/13612/10 "2021-07-01T18:11:51Z")

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@NathanD where in the model did you find the non-manifold issues?

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<div class="post-metadata">

**Author:** ![NathanD](https://avatars.discourse-cdn.com/v4/letter/n/dec6dc/32.png) [@NathanD](https://discourse.shapr3d.com/u/NathanD)\
**Post date:** [July 3, 2021, 6:02am UTC](https://discourse.shapr3d.com/t/non-manifold-detection/13612/11 "2021-07-03T06:02:04Z")

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@Istvan these were the errors pointed out in mesh mixer.

 ![image](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/2X/5/512bc125d1f10634029d8e4251c612367b1dfeb6.jpeg)

I then went back into the model in Shapr, searched, and found it.

This is what I found viewing “inside” the part.

 ![image](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/2X/a/abcd7ba3c32342df8a5a4cf6526da8eef7db0598.jpeg)

 ![image](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/2X/7/737c0526e8ae12e57a4649c913ec4b283cbc97ac.jpeg)

Like I said, I would have never found it. 🥴

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<div class="post-metadata">

**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:** [July 3, 2021, 3:22pm UTC](https://discourse.shapr3d.com/t/non-manifold-detection/13612/12 "2021-07-03T15:22:00Z")

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How did you rectify the last one?

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<div class="post-metadata">

**Author:** ![NathanD](https://avatars.discourse-cdn.com/v4/letter/n/dec6dc/32.png) [@NathanD](https://discourse.shapr3d.com/u/NathanD)\
**Post date:** [July 3, 2021, 4:45pm UTC](https://discourse.shapr3d.com/t/non-manifold-detection/13612/13 "2021-07-03T16:45:51Z")

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@Oregonerd mesh mixer has a repair function for the mesh body. One click fix.

I have not tried to fix the Shapr model.