Sebastien,
I am bringing vtk.js via npm in the production code. This is package.json part:
“vtk.js”: “^14.15.4”,
“worker-loader”: “^3.0.1”
In jsfifddle it’s the CDN (latest version): https://unpkg.com/vtk.js@18.1.12/vtk.js
The “field” entry in the .setScalars() call is probably wrong. I will remove it. So as long as your example above (with ‘velocity’) field works it would satisfy my requirements. Unfortunately it seems like vtkDataArray.newInstance() call is what crashing the code at the moment.