# Model does not close after hollowing

**URL:** <https://discourse.slicer.org/t/model-does-not-close-after-hollowing/5232>\
**Category:** Support\
**Tags:** segmentation\
**Created:** [December 30, 2018, 6:51pm UTC](https://discourse.slicer.org/t/model-does-not-close-after-hollowing/5232 "2018-12-30T18:51:53Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![feng](https://avatars.discourse-cdn.com/v4/letter/f/82dd89/32.png) [@feng](https://discourse.slicer.org/u/feng)\
**Post date:** [December 30, 2018, 6:51pm UTC](https://discourse.slicer.org/t/model-does-not-close-after-hollowing/5232/1 "2018-12-30T18:51:53Z")

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Anyone konws why this happens? I chose inside surface in this case

 ![43347DB6-3CCE-4B84-B76E-521E69FE3881](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/9/f/9f3ba6acd73b28006ba3daaa7c209148d87f779b.jpeg)

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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:** [December 30, 2018, 7:11pm UTC](https://discourse.slicer.org/t/model-does-not-close-after-hollowing/5232/2 "2018-12-30T19:11:37Z")

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The shell is very thin. Either make it thicker (in number of voxels; if you d to decrease physical thickness then you may need to decrease voxel spacing of the segmentation by clicking the button next to master volume selector) or disable surface smoothing (option available in the dropdown menu of the Show 3D button).

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**Author:** ![feng](https://avatars.discourse-cdn.com/v4/letter/f/82dd89/32.png) [@feng](https://discourse.slicer.org/u/feng)\
**Post date:** [December 30, 2018, 7:40pm UTC](https://discourse.slicer.org/t/model-does-not-close-after-hollowing/5232/3 "2018-12-30T19:40:58Z")

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Solved. Thank you very much professor!