# Check surface meshes generated with the surface toolbox

**URL:** <https://discourse.slicer.org/t/check-surface-meshes-generated-with-the-surface-toolbox/44207>\
**Category:** Support\
**Tags:** surface-toolbox\
**Created:** [August 26, 2025, 3:53pm UTC](https://discourse.slicer.org/t/check-surface-meshes-generated-with-the-surface-toolbox/44207 "2025-08-26T15:53:57Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![DaSt](https://avatars.discourse-cdn.com/v4/letter/d/e56c9b/32.png) [@DaSt](https://discourse.slicer.org/u/DaSt)\
**Post date:** [August 26, 2025, 3:53pm UTC](https://discourse.slicer.org/t/check-surface-meshes-generated-with-the-surface-toolbox/44207/1 "2025-08-26T15:53:57Z")

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Dear All,

I’m using the Surface Toolbox, specifically Uniform Remesh, via the Python API to generate STL surface meshes with a target edge length. Occasionally the resulting STL is not watertight (e.g., open boundaries / non-manifold elements).

I wanted to ask if there is a slicer inbuild solution to check for watertightness or fix falsely stl files/surface meshes?

Context:

- Slicer Version 5.8.1
- OS: Windows 11

Thanks in advance and best,

Daniel

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**Author:** ![pieper](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/pieper/32/8_2.png) [@pieper](https://discourse.slicer.org/u/pieper)\
**Post date:** [August 26, 2025, 5:19pm UTC](https://discourse.slicer.org/t/check-surface-meshes-generated-with-the-surface-toolbox/44207/2 "2025-08-26T17:19:06Z")

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This discussion might help: [is there any way to check mesh is watertight? - Support - VTK](https://discourse.vtk.org/t/is-there-any-way-to-check-mesh-is-watertight/3169)

VTK classes like this are available in the Slicer python environment.

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**Author:** ![DaSt](https://avatars.discourse-cdn.com/v4/letter/d/e56c9b/32.png) [@DaSt](https://discourse.slicer.org/u/DaSt)\
**Post date:** [August 27, 2025, 2:59pm UTC](https://discourse.slicer.org/t/check-surface-meshes-generated-with-the-surface-toolbox/44207/3 "2025-08-27T14:59:49Z")

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Thanks Steve!

I’ll have a look at it, I also stumbled across trimesh which seems to also have the capability of repairing STLs

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**Author:** ![Przemek\_Czuma](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/przemek_czuma/32/80268_2.png) [@Przemek\_Czuma](https://discourse.slicer.org/u/Przemek_Czuma)\
**Post date:** [August 29, 2025, 4:54am UTC](https://discourse.slicer.org/t/check-surface-meshes-generated-with-the-surface-toolbox/44207/4 "2025-08-29T04:54:41Z")

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Hi,  
If it helps: I’m sealing the mesh in Blender after exporting it to STL from 3D Slicer. There are dedicated tools for this (the 3D Print add-on – quite effective). I also wrote my own add-on that checks for watertightness (in Polish it’s that tricky word: “wodoszczelna” 🙂 at the top of addon) and allows automating the available there mesh optimization methods, as well as performing a remesh to make the mesh less chaotic than the raw one from 3D Slicer (as in the illustration), smoothing it, reducing size etc. – basically preparing it for 3D printing.

If you don’t feel like using Blender, a good, simple, and effective tool is the Windows mesh repair service, for example through Bambu Studio.

Best regards 🙂

BEFORE REMESH:

 ![Zrzut ekranu 2025-08-29 063816](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/e/e/ee062fcb0cc325999090be7ac7d1ea06cc72023a.jpeg)

AFTER REMESH:

 ![Zrzut ekranu 2025-08-29 064259](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/a/1/a16865808ef04ec01a2f403bc8284581094d8d2f.jpeg)