# Mirroring a model

**URL:** <https://discourse.slicer.org/t/mirroring-a-model/18059>\
**Category:** Support\
**Tags:** dynamic-modeler\
**Created:** [June 10, 2021, 11:13am UTC](https://discourse.slicer.org/t/mirroring-a-model/18059 "2021-06-10T11:13:31Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![mohammed\_alshakhas](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/mohammed_alshakhas/32/10025_2.png) [@mohammed\_alshakhas](https://discourse.slicer.org/u/mohammed_alshakhas)\
**Post date:** [June 10, 2021, 11:13am UTC](https://discourse.slicer.org/t/mirroring-a-model/18059/1 "2021-06-10T11:13:31Z")

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i have this case of facia asymmertry , my purpose is to evaluatr zygoma position  
steps i followed  
1 segment the skull  
2 segment zygoma  
3 trnasform zygoma to model  
4 mirrror zygoma around x axis in suface model/ advance/ mirror

however i got it displace and not mirrored perfectly arounf x axis , i tried transformation to 3d position before mirroring and didnot fix it

any idea how to fix that ?

 ![Screen Shot 2021-06-10 at 14.08.59](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/f/8/f8b66ecfccd426df9e86749cfa59adaa43e2cb3c.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:** [July 21, 2021, 1:37am UTC](https://discourse.slicer.org/t/mirroring-a-model/18059/2 "2021-07-21T01:37:35Z")

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In general, x axis of the coordinate system that a mesh is defined in is not aligned with the anatomical left-right axis and the origin is not in the center, therefore after mirroring you need to register the mirrored parts to the original surface, using one of the many [registration methods available in Slicer.](https://slicer.readthedocs.io/en/latest/user_guide/registration.html)