I have a dataset with multiple structures which are shaped like irregular 3d tubes, I was wondering if it is possible to fit a spline through the approximate center of such structures (I have both isosurfaces and volume data) … Here is an example:
The operation you need is called skeletonization. I don’t believe VTK has a mesh skeletonizer or even a raster skeletonizer. Still, you can do it with its sister library, ITK, and you have, as you already guessed, to raster your mesh into a 3D volume: https://vtk.org/pipermail/vtkusers/2018-January/100722.html .