Sebastien, After struggling with different versions in Angular, I have rebuilt the test in Vue and it works perfectly, at least the vtkDataArray.newInstance call. There’s something fishy with trying to use Vtk.js with Angular. However, to answer your question the error I’ve been getting before switching over to Vue was always the same: "ERROR TypeError: “vtk_js_Sources_Common_Core__WEBPACK_IMPORTED_MODULE_13__.default.newInstance is not a function” even when I used the working solution with non-empty instantiation of dataArray. The issue might be related to Angular, which I gave up on, but even in JSFiddle when I changed the version to 14.15.4 I got “Uncaught ReferenceError: vtkDataArray is not defined”, which goes away when upgrading to version 18.