# What underlying concepts are being used going from segmentation to .STL

**URL:** <https://discourse.slicer.org/t/what-underlying-concepts-are-being-used-going-from-segmentation-to-stl/35898>\
**Category:** Support\
**Tags:** segmentation, python, stl\
**Created:** [May 3, 2024, 6:29pm UTC](https://discourse.slicer.org/t/what-underlying-concepts-are-being-used-going-from-segmentation-to-stl/35898 "2024-05-03T18:29:50Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![koenterheegde](https://avatars.discourse-cdn.com/v4/letter/k/67e7ee/32.png) [@koenterheegde](https://discourse.slicer.org/u/koenterheegde)\
**Post date:** [May 3, 2024, 6:29pm UTC](https://discourse.slicer.org/t/what-underlying-concepts-are-being-used-going-from-segmentation-to-stl/35898/1 "2024-05-03T18:29:50Z")

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I’m currently developing a program which has some of the same features as Slicer. Eventually, I get a .STL file and extract the centerline from it. However, when I apply this to my own generated .STL files, it doesn’t work compared to the ones being made in Slicer. It made me think that the segmentations/models are actually volumetric meshes instead of surface meshes, but I’m not sure whether I’m correct. And how does Slicer generate these volumetric meshes (if they are) from segmentations?  
Cheers.

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**Author:** ![muratmaga](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/muratmaga/32/3622_2.png) [@muratmaga](https://discourse.slicer.org/u/muratmaga)\
**Post date:** [May 3, 2024, 6:55pm UTC](https://discourse.slicer.org/t/what-underlying-concepts-are-being-used-going-from-segmentation-to-stl/35898/2 "2024-05-03T18:55:15Z")

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please read this document for answers to your questions:  
[Image Segmentation — 3D Slicer documentation](https://slicer.readthedocs.io/en/latest/user_guide/image_segmentation.html)