After importing the newest vtk.js from https://unpkg.com/vtk.js@8.4.2/dist/vtk.js I realized that the vtkArrowSource is not part of it. Before I used an older version, where it wasn’t included either but I hoped this would have been resolved by now. The only place I can find the vtkArrowSource is the npm package :frowning:

PS. The same is true for the Circle- and the CylinderSource

Feel free to submit a Merge request with a fix. This can be quickly integrated.