# Model registration from fiducial point

**URL:** <https://discourse.slicer.org/t/model-registration-from-fiducial-point/25462>\
**Category:** Support\
**Created:** [September 28, 2022, 9:20am UTC](https://discourse.slicer.org/t/model-registration-from-fiducial-point/25462 "2022-09-28T09:20:12Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![jegberink](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/jegberink/32/16031_2.png) [@jegberink](https://discourse.slicer.org/u/jegberink)\
**Post date:** [September 28, 2022, 9:20am UTC](https://discourse.slicer.org/t/model-registration-from-fiducial-point/25462/1 "2022-09-28T09:20:12Z")

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Hello everyone,

I’ve overlapped a preoperative femur and postoperative femur, where the femoral head position was changed. I’ve overlapped them using ALPACA to measure the rotations and translations.

 ![before](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/9/9/995648eaec25bb9b8215a3f28f3184b00044bade.png)  
 ![image](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/2/7/27f452e2876d9cbe0757bdb41d2d551ee8be032d.png)

Now i managed to use the “rotate a node around a specified point” script to be able to rotate the head from a point relative to its shaft, so we have a singular point to measure from with other patients.

However, i can not figure out how to measure the ALPACA overlap from this new point, is there a way to do this.

Thank you in advance.