# Segmented, exported surfaces overlap (unexpected)

**URL:** <https://discourse.slicer.org/t/segmented-exported-surfaces-overlap-unexpected/33012>\
**Category:** Support\
**Created:** [November 24, 2023, 7:56pm UTC](https://discourse.slicer.org/t/segmented-exported-surfaces-overlap-unexpected/33012 "2023-11-24T19:56:56Z")\
**Posts on this page:** 1\
**Showing post:** 9

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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:** [November 29, 2023, 12:04am UTC](https://discourse.slicer.org/t/segmented-exported-surfaces-overlap-unexpected/33012/9 "2023-11-29T00:04:23Z")

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@mau_igna_06 it would be good if you could try the [JointSmoothing option from the older ModelMaker](https://slicer.readthedocs.io/en/latest/user_guide/modules/modelmaker.html#:~:text=Joint%20Smoothing%20(JointSmoothing)%3A%20This%20will%20ensure%20that%20all%20resulting%20models%20fit%20together%20smoothly%2C%20like%20jigsaw%20puzzle%20pieces.%20Otherwise%20the%20models%20will%20be%20smoothed%20independently%20and%20may%20overlap.). That mode was specifically added to provide watertight boundaries because the vertices of both models were moved identically during the smoothing process, so there was never any gap between the meshes for adjacent segments. There may still be some aspects of the older code that need to be incorporated in the segmentations infrastructure.

This topic has come up before, but it’s still not clear to me that we can easily get the same output meshes that we get with ModelMaker.

> [@surface rendering of many segments](https://discourse.slicer.org/t/surface-rendering-of-many-segments/4044/4):
>
> We have that option in Smoothing effect but not in the automatic conversion between segment representations. The assumption is that smoothing operation in “binary labelmap to closed surface” conversion is only used for removing staircase artifacts and so it does not require adjustment of the geometry. We would need to implement some new mechanism in segmentation infrastructure to allow joint conversion of multiple segments, because right now conversion happens segment by segment.

> [@Exported STL files from the segmentation has intersection/penetration](https://discourse.slicer.org/t/exported-stl-files-from-the-segmentation-has-intersection-penetration/6692):
>
> Operating system: Windows 10 Slicer version: 4.10.1 Hi everyone, I want to create models for mandible and teeth from a CBCT scan. After importing the DICOM file to 3Dslicer and completing the segmentation process I used segmentations/export to export the segmentations as STL models. Then I import those STL files into Meshmixer and I found out the models have intersections! (the surface of the teeth model penetrates the surface of the bone model as you can see in the image). I noticed that 3D …

> [@Exported STL files from the segmentation has intersection/penetration](https://discourse.slicer.org/t/exported-stl-files-from-the-segmentation-has-intersection-penetration/6692/9):
>
> @Tekk_ya you might try a slightly different pathway to get “watertight” models. export the segmentation to a label map run the ModelMaker module with the “Joint Smoothing” operation enabled what this will do is apply the same smoothing operation to matching vertices from the different segments so that no gaps are introduced. In the example below the yellow/green surfaces use the default and the red/blue use Joint Smoothing. @lassoan I don’t see that the segmentation closed surface option ex…

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