# Compare models trouble shooting

**URL:** <https://discourse.slicer.org/t/compare-models-trouble-shooting/8063>\
**Category:** Support\
**Created:** [August 16, 2019, 4:52pm UTC](https://discourse.slicer.org/t/compare-models-trouble-shooting/8063 "2019-08-16T16:52:35Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Andrew\_Kanawati](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/andrew_kanawati/32/3983_2.png) [@Andrew\_Kanawati](https://discourse.slicer.org/u/Andrew_Kanawati)\
**Post date:** [August 16, 2019, 4:52pm UTC](https://discourse.slicer.org/t/compare-models-trouble-shooting/8063/1 "2019-08-16T16:52:35Z")

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I am having trouble comparing and aligning two models.

I am registering the fixed segment as a CT scan.

Then for the moving segment, created a new volume from a STL (converted to a segment).

However the 2 models are not aligning.

 ![46%20PM](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/a/7/a7cb4a1c2d3b7cb1fed0aa10eb4173803cc5cc8f.jpeg)

I would like the models to align to then compare models and perform Hausdorff distances.

Thanks very much.

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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:** [August 17, 2019, 7:34pm UTC](https://discourse.slicer.org/t/compare-models-trouble-shooting/8063/2 "2019-08-17T19:34:34Z")

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You can align two segments using Segment Registration extension then compare them using Segment Comparison module (provided by SlicerRT extension).

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<div class="post-metadata">

**Author:** ![Andrew\_Kanawati](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/andrew_kanawati/32/3983_2.png) [@Andrew\_Kanawati](https://discourse.slicer.org/u/Andrew_Kanawati)\
**Post date:** [August 19, 2019, 1:31pm UTC](https://discourse.slicer.org/t/compare-models-trouble-shooting/8063/3 "2019-08-19T13:31:54Z")

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Thanks

I was able to align segments, however the moving segment is not appearing on the 3D view as it is in the axial/sag/cor reconstructions.

Thanks again

 ![31%20AM](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/e/e/eecf4c4d0c0b013d8a7a71e52a2d725a02a7b77b.jpeg)

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**Author:** ![Juicy](https://avatars.discourse-cdn.com/v4/letter/j/74df32/32.png) [@Juicy](https://discourse.slicer.org/u/Juicy)\
**Post date:** [August 22, 2019, 10:09am UTC](https://discourse.slicer.org/t/compare-models-trouble-shooting/8063/4 "2019-08-22T10:09:15Z")

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Have you tried going into ‘Segment Editor’ module and ensuring that the ‘Show 3d’ button at the top of the module is pressed?