# Osteotomy Planner v2.0

**URL:** <https://discourse.slicer.org/t/osteotomy-planner-v2-0/18384>\
**Category:** Support\
**Tags:** build, python, surgical-planning\
**Created:** [June 29, 2021, 2:27am UTC](https://discourse.slicer.org/t/osteotomy-planner-v2-0/18384 "2021-06-29T02:27:05Z")\
**Posts on this page:** 1\
**Showing post:** 9

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**Author:** ![Fluvio\_Lobo](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/fluvio_lobo/32/81262_2.png) [@Fluvio\_Lobo](https://discourse.slicer.org/u/Fluvio_Lobo)\
**Post date:** [July 12, 2021, 1:29am UTC](https://discourse.slicer.org/t/osteotomy-planner-v2-0/18384/9 "2021-07-12T01:29:54Z")

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@lassoan, @pieper,

Below is my approach at using **Fiducial Registration** to create a **Warping** transform and deform the skin of the model to match the motion of the osteotomies.

1. I appended the model of the Skull to both the Original Orbital Bandeau and the Advanced/Modified Bandeau, creating a “Source” and “Target” model. My goal here is to ensure that the transformation requires a deformation of the model, rather than simply resulting in a translation.

 ![source](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/8/3/83fce191b1cde4af3dd5141e759ce75b7b35f10d.png)  
 ![target](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/5/5/55d2d3307bfe4cf37a81c513c18911537c7db156.png)

1. I added “From” and “To” Fiducials to both the “Source” and “Target” models, with some of these coinciding on the Skull

 ![source_with_fiducials.PNG](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/8/0/8098f8a87e2d70e63e1becd0cf53571910a8c59f.jpeg)  
 ![target_with_fiducials.PNG](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/8/a/8a57ef26e6307ebb650d70eadc518c848d4a4631.jpeg)

1. I generated a “Warping” transform using the Fiducial Registration Module and applied it to a model of the patient’s soft tissue.

 ![source_screen](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/2/2/2259ffa15a38b9b2e8e04e630ef5d11d3c5e4740.jpeg)  
 ![target_skin_screen](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/7/1/71d30091129f47127d91ab36f5f2d28b68386885.jpeg)

This seemed to work but I believe it is influenced by areas with more fiducials. The right orbit of the skull model has like 2-3 more fiducials and there seems to be more deformation on that side. A simple overlay of the two models shows this.

 ![skin_overlay](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/a/9/a90c2e25f38c89eceafd3a95467c9ec8134a298e.jpeg)

So, my questions are:

1. Is this a valid approach?
2. Is this an efficient approach? or, is there a more generalized solution?
3. Is there a way of using the surface vertices of the models as fiducials?

Thank you!

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