# Orientation issue loading vtk mesh

**URL:** <https://discourse.slicer.org/t/orientation-issue-loading-vtk-mesh/10641>\
**Category:** Support\
**Created:** [March 11, 2020, 12:49pm UTC](https://discourse.slicer.org/t/orientation-issue-loading-vtk-mesh/10641 "2020-03-11T12:49:33Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![alixchcl](https://avatars.discourse-cdn.com/v4/letter/a/d6d6ee/32.png) [@alixchcl](https://discourse.slicer.org/u/alixchcl)\
**Post date:** [March 11, 2020, 12:49pm UTC](https://discourse.slicer.org/t/orientation-issue-loading-vtk-mesh/10641/1 "2020-03-11T12:49:34Z")

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Operating system: Linux  
Slicer version: 4.11.0 (-2020-03-03)  
Expected behavior:  
Actual behavior:

Hi, I am trying Slicer new version, and I encounter orientation problems while reading vtk meshes. The following segmentation is supposed to match the thalamus.

 ![Slicer3D521](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/4/b/4bbc7b178df637ee5706dd248ab6168636afb1f4.jpeg)

However, one of my colleague is using Slicer version 4.11.0-2020-01-18 on Mac OS and does not encounter the same trouble, loading exactly the same files.

 ![SlicerSara](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/c/9/c9af8736a46c93caec76870b82a5fbaf3eb47bb9.jpeg)

Would anyone know what is happening there ?

Thanks a lot in advance!

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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 11, 2020, 1:37pm UTC](https://discourse.slicer.org/t/orientation-issue-loading-vtk-mesh/10641/2 "2020-03-11T13:37:40Z")

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We have updated Slicer-4.11.0 on 2020-02-26 to consistently save all data in LPS coordinate system and assume all data to be stored in LPS coordinate system by default. See details in this post:

> [@Model files are now saved in LPS coordinate system](https://discourse.slicer.org/t/model-files-are-now-saved-in-lps-coordinate-system/10446):
>
> While Slicer uses RAS coordinate system internally, images, transforms, and markups files are stored in LPS coordinate system, because DICOM and all medical image computing software (maybe except a few very old ones) uses LPS coordinate system in files. However, Slicer has been still using its internal RAS coordinate system in mesh files (STL, VTK, VTP, OBJ, PLY), which [caused issues when interfacing with third-party software](https://issues.slicer.org/view.php?id=4445). Starting from tomorrow (Slicer-4.11.0-2020-02-26, revision 28794), …

If you have any remaining questions or concerns then please post them here.