vtkArrow are not properly rendered

[bourdaisj]

Description

Trying to synchronize vtkArrowSource, either via classic dataset mapper or even vtkGlyph3DMapper
Reproduced with 9.7.20260802.dev0 but the issue seems much older.
I check a few other sources (cone, cylinder, sphere) and they are not impacted.

Where does the issue originate?

Upstream Project (VTK itself)

Version Information

trame-vtklocal==1.2.0, vtk==9.7.20260802.dev0

Steps to Reproduce

repro_arrow.py

Run the provided script. Notice the correctly rendered arrow in the VTK native window, and the wrong rendering in the browser render view.

Observed rendering

Expected Rendering

[bourdaisj]

no rush, but any idea about this @jspanchu or @jourdain ?

[jspanchu]

The vtkArrowSource just applies transform filter on a vtkCylinderSource and a vtkConeSource, then appends both into one vtkPolyData. nothing obvious comes to mind. I'll try the rerpoducer, thanks for sharing that.

[jspanchu]

@bourdaisj This occurs due to wasm32 trying to hydrate a vtkIdTypeArray on the wasm32 side with a vtkIdTypeArray received from a server which is 64-bit.

Just use wasm64,

        html_render_view = vtklocal.LocalView(
            render_window,
            config=("{ mode: 'wasm64' }",),
            ctx_name="wasm_view",
        )

if that's not possible due to browser constraint (safari does not support wasm64), then do this.

source.Update()
source.GetOutput().GetPolys().ConvertTo32BitStorage()

I can confirm both of these work.

[bourdaisj]

Thanks! using wasm64 fix it on my end too.
Let's wait for your MR being merged before closing this (?)