# Model registration

**URL:** <https://discourse.slicer.org/t/model-registration/8177>\
**Category:** Support\
**Created:** [August 26, 2019, 3:20pm UTC](https://discourse.slicer.org/t/model-registration/8177 "2019-08-26T15:20:14Z")\
**Posts on this page:** 7\
**Page:** 1

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**Author:** ![Jainey](https://avatars.discourse-cdn.com/v4/letter/j/a88e57/32.png) [@Jainey](https://discourse.slicer.org/u/Jainey)\
**Post date:** [August 26, 2019, 3:20pm UTC](https://discourse.slicer.org/t/model-registration/8177/1 "2019-08-26T15:20:15Z")

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Hi  
Thank you for all the previous inputs; this seems to be working.

One more question- When I register two models the mean distance appear in decimals , say 0.65 but when I check the translations on the transforms module for the linear transforms they are in the range of 34 mm, 44 mm eat on xy and z. How could this happen. Could someone please let me know. In reality the distance between the centre of the models would only change 1-2 mm.

Thanks a lot

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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 27, 2019, 1:56pm UTC](https://discourse.slicer.org/t/model-registration/8177/2 "2019-08-27T13:56:42Z")

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Which module do you use to register the models?

Fiducial registration wizard reports residual error. You can find registration translation/rotation values in Transforms module.

> [@Jainey](#):
>
> In reality the distance between the centre of the models would only change 1-2 mm.

Can you post screenshots - before/after registration, GUI of the module you use for registration, and resulting transform shown in Transforms module?

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**Author:** ![Jainey](https://avatars.discourse-cdn.com/v4/letter/j/a88e57/32.png) [@Jainey](https://discourse.slicer.org/u/Jainey)\
**Post date:** [August 27, 2019, 4:54pm UTC](https://discourse.slicer.org/t/model-registration/8177/3 "2019-08-27T16:54:55Z")

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Thanks Prof @lassoan  
I use mode to model registration with ICP algorithm

 ![28](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/d/7/d78262e1e17acfa11708bb58ad5b4e7651dcd166.jpeg)  
 ![26](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/4/2/427546a1f194edf90e5a31ef0293c816b2fe8c90.jpeg) Snip 2019-08-28 02.26.26.png

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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 27, 2019, 5:16pm UTC](https://discourse.slicer.org/t/model-registration/8177/4 "2019-08-27T17:16:02Z")

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Thanks for the additional information, it was useful.

> [@Jainey](#):
>
> In reality the distance between the centre of the models would only change 1-2 mm.

As you say, the distance between the _center_ of the models is 1-2mm. However, the translation component that you see in Transforms module is the translation at the origin (RAS=(0,0,0) position). To get translation at the center of the model, get the center of the model and transform that point coordinate using the transform.

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**Author:** ![Jainey](https://avatars.discourse-cdn.com/v4/letter/j/a88e57/32.png) [@Jainey](https://discourse.slicer.org/u/Jainey)\
**Post date:** [August 28, 2019, 12:47am UTC](https://discourse.slicer.org/t/model-registration/8177/5 "2019-08-28T00:47:38Z")

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Thanks Prof @lassoan  
How could I do that please. Or any particular point in the model. Thank you 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 28, 2019, 2:51pm UTC](https://discourse.slicer.org/t/model-registration/8177/6 "2019-08-28T14:51:16Z")

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You can retrieve the VTK transform from the transform node and then use its `TransformPoint` method to transform a point coordinate. Search for `TransformPoint` in [script repository](https://www.slicer.org/wiki/Documentation/Nightly/ScriptRepository) for examples.

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**Author:** ![johny723](https://avatars.discourse-cdn.com/v4/letter/j/7ea924/32.png) [@johny723](https://discourse.slicer.org/u/johny723)\
**Post date:** [April 17, 2025, 2:05pm UTC](https://discourse.slicer.org/t/model-registration/8177/8 "2025-04-17T14:05:47Z")

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Hi, I need help. I am trying to register a segmented sacrum from CT onto a sacrum from MRI. It is the same patient. When I use “model registration” I do not see the output model. What is wrong?

 ![Snímka obrazovky 2025-04-17 160302](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/9/b/9bfbfcecbef540bd24fe4431338a06bb1655f9e4.png)

I tried 5,6.1, 5.8.1 and even 5.9, but it does not work. I also do not see the transforms, just this rather small table