# Save nrrd as stl but only the outside

**URL:** <https://discourse.slicer.org/t/save-nrrd-as-stl-but-only-the-outside/10653>\
**Category:** Support\
**Created:** [March 12, 2020, 4:05am UTC](https://discourse.slicer.org/t/save-nrrd-as-stl-but-only-the-outside/10653 "2020-03-12T04:05:01Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![guido\_galetto](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/guido_galetto/32/6260_2.png) [@guido\_galetto](https://discourse.slicer.org/u/guido_galetto)\
**Post date:** [March 12, 2020, 4:05am UTC](https://discourse.slicer.org/t/save-nrrd-as-stl-but-only-the-outside/10653/1 "2020-03-12T04:05:01Z")

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Hi! I want to save a .nrrd file as a stl, but i want only the superficial mesh. I need the skin to make a 3d orthosis.

THanks!

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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 12, 2020, 4:08am UTC](https://discourse.slicer.org/t/save-nrrd-as-stl-but-only-the-outside/10653/2 "2020-03-12T04:08:09Z")

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STL file can only store a surface mesh. If your problem is that the extracted skin surface segment is not solid then either use Smoothing effect or Wrap Solidify effect (provided by [SurfaceWrapSolidify extension](https://github.com/sebastianandress/Slicer-SurfaceWrapSolidify)).