# Save a binary segmentation of the surface voxels of a segment.

**URL:** <https://discourse.slicer.org/t/save-a-binary-segmentation-of-the-surface-voxels-of-a-segment/22542>\
**Category:** Support\
**Tags:** segmentation\
**Created:** [March 16, 2022, 5:15pm UTC](https://discourse.slicer.org/t/save-a-binary-segmentation-of-the-surface-voxels-of-a-segment/22542 "2022-03-16T17:15:59Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Steven\_A](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/steven_a/32/14596_2.png) [@Steven\_A](https://discourse.slicer.org/u/Steven_A)\
**Post date:** [March 16, 2022, 5:15pm UTC](https://discourse.slicer.org/t/save-a-binary-segmentation-of-the-surface-voxels-of-a-segment/22542/1 "2022-03-16T17:15:59Z")

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Hello, I am wondering if there is a method to save a binary labelmap of the surface voxels of a segment? If I’m not mistaken, there was a method to do this, but I don’t remember how.

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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 16, 2022, 7:46pm UTC](https://discourse.slicer.org/t/save-a-binary-segmentation-of-the-surface-voxels-of-a-segment/22542/2 "2022-03-16T19:46:21Z")

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You can use “Hollow” effect to keep boundary voxels (up to the specified thickness). If you need to extract position of boundary points then the closed surface representation is probably more appropriate.

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**Author:** ![Steven\_A](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/steven_a/32/14596_2.png) [@Steven\_A](https://discourse.slicer.org/u/Steven_A)\
**Post date:** [March 17, 2022, 7:09am UTC](https://discourse.slicer.org/t/save-a-binary-segmentation-of-the-surface-voxels-of-a-segment/22542/3 "2022-03-17T07:09:57Z")

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Thank you very much.