# Crop surface mesh (vtk file)

**URL:** <https://discourse.slicer.org/t/crop-surface-mesh-vtk-file/2405>\
**Category:** Support\
**Created:** [March 22, 2018, 7:35pm UTC](https://discourse.slicer.org/t/crop-surface-mesh-vtk-file/2405 "2018-03-22T19:35:35Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![Joelle](https://avatars.discourse-cdn.com/v4/letter/j/50afbb/32.png) [@Joelle](https://discourse.slicer.org/u/Joelle)\
**Post date:** [March 22, 2018, 7:35pm UTC](https://discourse.slicer.org/t/crop-surface-mesh-vtk-file/2405/1 "2018-03-22T19:35:35Z")

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Hi

I got a surface mesh (vtk PolyData) and would like to extract a certain part of it and save it as a new file. All the tutorials I found were for volume mesh.

Thanks for the help.

Cheers Joëlle

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**Author:** ![lassoan](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/lassoan/32/13_2.png) [@lassoan](https://discourse.slicer.org/u/lassoan)\
**Post date:** [March 22, 2018, 8:04pm UTC](https://discourse.slicer.org/t/crop-surface-mesh-vtk-file/2405/2 "2018-03-22T20:04:14Z")

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All tutorials are for surface mesh. The segment editor always creates a closed surface mesh. Maybe you mean that you would like to create an open surface where you cut?

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**Author:** ![Joelle](https://avatars.discourse-cdn.com/v4/letter/j/50afbb/32.png) [@Joelle](https://discourse.slicer.org/u/Joelle)\
**Post date:** [March 24, 2018, 7:22pm UTC](https://discourse.slicer.org/t/crop-surface-mesh-vtk-file/2405/3 "2018-03-24T19:22:33Z")

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I use the following model. I’m not sure what you mean by open surface. I assume you mean a volume which isn’t closed.

 ![15](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/2/c/2c41fb990e431f7d9cce0389ccf59a0124a33d40.jpeg) ![15](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/2/c/2c41fb990e431f7d9cce0389ccf59a0124a33d40.jpeg) ![15](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/2/c/2c41fb990e431f7d9cce0389ccf59a0124a33d40.jpeg)

I would like to cut a certain area of this model. Is there an easy way to do this?

Thanks in advance.

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<div class="post-metadata">

**Author:** ![lassoan](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/lassoan/32/13_2.png) [@lassoan](https://discourse.slicer.org/u/lassoan)\
**Post date:** [March 24, 2018, 8:53pm UTC](https://discourse.slicer.org/t/crop-surface-mesh-vtk-file/2405/4 "2018-03-24T20:53:22Z")

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OK. For this, since you probably want to keep the open surface, probably the best tool is the [ModelClip module](https://www.slicer.org/wiki/Documentation/Nightly/Extensions/ModelClip) (available in ModelClip extension).

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**Author:** ![Joelle](https://avatars.discourse-cdn.com/v4/letter/j/50afbb/32.png) [@Joelle](https://discourse.slicer.org/u/Joelle)\
**Post date:** [March 25, 2018, 6:03pm UTC](https://discourse.slicer.org/t/crop-surface-mesh-vtk-file/2405/5 "2018-03-25T18:03:04Z")

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Hey  
My goal is to compare symmetry of the surface. But only on a certain part of the model. For this I need to be able to cut the model and save it as a new one.

I tried to work with ROI but I didn’t manage to only compare the ROI with each other.

To compare the surface I already asked once 🙂 (see link) [Surface similarity of a model](https://discourse.slicer.org/t/surface-similarity-of-a-model/2287)  
Thanks again