Add-on to fit a cylinder to vertices

I previously updated two small add-ons that can fit a line or a plane to a collection of vertices and was asked if it was possible to create an add-on that fits a cylinder.

That is a bit more challenging though, but luckily there are people who spend some serious time on designing an algorithm and even providing code (see references below).

Based on that I created a small add-on that can indeed fit a cylinder to a collection of selected vertices. Note that it fits a cylinder where the vertices lie as closely as possible on the surface of the cylinder (see image). If you want to fit a cylinder that encloses all vertices, so more of a solid rod, simply use the linefit add-on and align a cylinder to the best fit line.

Usage

Simply download cyclinderfit.zip from the repo and install and enable the add-on from this zip-file.

Then select the mesh with the vertices you want to fit the cylinder to and select Fit cylinder from the Add menu (in edit mode). The new cylinder object will be added as a separate object that will be in edit mode.

Code availability

The code is available in this GitHub repository.

References

The cylinder fitting code was adapted from code in Xing Jiepan's repo, which in turn was based on the algorithms described in this paper by David Eberly.

To remove dependencies on external packages (except numpy, which is included with Blender), we replaced calls to the scikit.optimize.minimize function with a different implementation of Powells' minimization function from the Sherpa code-base of the Chandra project.