# Display heatmap of Hounsfield values on registered surface object for cortical bone contact

**URL:** <https://discourse.slicer.org/t/display-heatmap-of-hounsfield-values-on-registered-surface-object-for-cortical-bone-contact/42389>\
**Category:** Development\
**Tags:** registration\
**Created:** [April 1, 2025, 6:35am UTC](https://discourse.slicer.org/t/display-heatmap-of-hounsfield-values-on-registered-surface-object-for-cortical-bone-contact/42389 "2025-04-01T06:35:22Z")\
**Posts on this page:** 1\
**Showing post:** 6

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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:** [April 8, 2025, 3:08pm UTC](https://discourse.slicer.org/t/display-heatmap-of-hounsfield-values-on-registered-surface-object-for-cortical-bone-contact/42389/6 "2025-04-08T15:08:08Z")

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> This has already been done, and there’s already some sort of extension available

Yes, the Pedicle Screw Simulator extension does exactly this:

[![](https://img.youtube.com/vi/XN3Tp8jaYdQ/maxresdefault.jpg "3D Slicer - Pedicle Screw Surgical Simulator") ](https://www.youtube.com/watch?v=XN3Tp8jaYdQ&t=121)

I don’t think you need to use this extension for your project, because your models are different, you position them differently (in current Slicer versions it is very easy to position models using [interactive transformation handles](https://discourse.slicer.org/t/new-feature-interactive-transformation-adjustable-center-of-rotation/36974)) and it takes just a few clicks to copy CT values to the model points.

> If not, whether it’s feasible and a reasonably achievable goal for someone with some (but not extensive) experience coding in Slicer

You don’t need any coding to get started. If you want to streamline the processing (minimize number of clicks) or fully automate it then you can do that with Python scripting. If you have specific questions you can ask questions here, or for getting more substantial help or developing complete solutions you can contact [Slicer Commercial Partners](https://www.slicer.org/commercial-use.html#commercial-partners).

> If there are any existing extensions or functions that would give me access to vertex points on a registered surface model, and allow me to then probe the nearest voxel for its intensity (HU) values

`Probe volume with model` module does exactly this.

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_[View the full topic](https://discourse.slicer.org/t/display-heatmap-of-hounsfield-values-on-registered-surface-object-for-cortical-bone-contact/42389)._