# Curvature, torsion from VMTK

**URL:** <https://discourse.slicer.org/t/curvature-torsion-from-vmtk/45652>\
**Category:** Support\
**Tags:** vmtk, centerlines, vmtk-centerline\
**Created:** [January 1, 2026, 5:24pm UTC](https://discourse.slicer.org/t/curvature-torsion-from-vmtk/45652 "2026-01-01T17:24:12Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![kuoi](https://avatars.discourse-cdn.com/v4/letter/k/2acd7d/32.png) [@kuoi](https://discourse.slicer.org/u/kuoi)\
**Post date:** [January 1, 2026, 5:24pm UTC](https://discourse.slicer.org/t/curvature-torsion-from-vmtk/45652/1 "2026-01-01T17:24:12Z")

</div>

Hello, I am using the Extract Centerline module. I obtained one centerline and one table containing a single line with a pair of curvature and torsion values.

I noticed that curvature and torsion are reported in the exported table called “centerline quantification”. I assume these values are averages. As stated in the [document](https://github.com/vmtk/SlicerExtension-VMTK/blob/master/Docs/ExtractCenterline.md): “Geometrical properties (length, average radius, curvature, torsion, tortuosity)”. However, I also noticed that the [code comment](https://github.com/vmtk/SlicerExtension-VMTK/blob/283a8520ae2669f1a25766dd00a3e4f4e907a5c0/ExtractCenterline/ExtractCenterline.py#L880) does not explicitly mention that these values are averages. Therefore, I am not sure whether my understanding is correct.

If these values are averages, could you advise on whether there are any approaches to estimate a fixed curvature and a fixed torsion value that best fit the currently extracted centerline?

I am considering using a sum of squared errors approach and fitting the parameters via the Python console to obtain these two values. Would this be a reasonable strategy?

Thanks a lot.