# vtk file superimposition

**URL:** <https://discourse.slicer.org/t/vtk-file-superimposition/10028>\
**Category:** Support\
**Created:** [January 30, 2020, 2:30pm UTC](https://discourse.slicer.org/t/vtk-file-superimposition/10028 "2020-01-30T14:30:46Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![nayansi.jha](https://avatars.discourse-cdn.com/v4/letter/n/ebca7d/32.png) [@nayansi.jha](https://discourse.slicer.org/u/nayansi.jha)\
**Post date:** [January 30, 2020, 2:30pm UTC](https://discourse.slicer.org/t/vtk-file-superimposition/10028/1 "2020-01-30T14:30:46Z")

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How can we save two vtk superimposed files( as a single file)?  
For example- right condyle models of the same patient taken at two different time points.

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**Author:** ![timeanddoctor](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/timeanddoctor/32/5839_2.png) [@timeanddoctor](https://discourse.slicer.org/u/timeanddoctor)\
**Post date:** [January 30, 2020, 2:39pm UTC](https://discourse.slicer.org/t/vtk-file-superimposition/10028/2 "2020-01-30T14:39:49Z")

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Yes, there are many methods:  
1、you can use the merge models module

 ![image](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/4/7/47d3f811695954af5712bfc531142dd6d3604281.png)  
2、you can import the models to a segmentation and then have a operation

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<div class="post-metadata">

**Author:** ![timeanddoctor](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/timeanddoctor/32/5839_2.png) [@timeanddoctor](https://discourse.slicer.org/u/timeanddoctor)\
**Post date:** [January 30, 2020, 2:50pm UTC](https://discourse.slicer.org/t/vtk-file-superimposition/10028/3 "2020-01-30T14:50:33Z")

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If you want to alin the different models you can use the ‘fiducial registration’ in IGT and analyse the different with the ‘model to model distance’ module