VTK Mesh (unstructured grid) reader

[aylward]

Thoughts on possible next steps:

• 1. itk.js Mesh to vtk.js vtkPolyData in WebAssembly. This will allow use to use .vtk and other ITK-supported mesh file formats.
• 2. A vtk.js helper class similar to ITKImageReader for PolyData
• 3. PVG adds support for this class
• 4. We start building some VTK PolyData IO classes to WebAssembly modules
• 4.b. ITK SpatialObject to VTK PolyData classes to WebAssembly module(s)
• 5. We start building some VTK Unstructured Grid IO classes to WebAssembly modules but include a filter to output PolyData
• 6 (?). Independent Unstructured Grid to PolyData WebAssembly support, vtk.js Unstructured Grid support, Unstructured Grid IO WebAssembly

I think it might be a good test for vtk-emscripten - IO and conversion class.

[thewtex]

Yes! 👾 🎇 💖

Starting on this.

Inserted 4.b) - ITK SpatialObject to VTK PolyData :-D

[wschroed]

It might be better if spatial objects are "mapped" to VTK implicit functions, they are nearly the same thing. Then in VTK, there are tools for generating surfaces (ie polydata), selecting and extracting data etc with implicit functions. But depending on workflow there are probably a couple of different paths to take....

…

On Thu, Feb 7, 2019 at 2:13 PM Matt McCormick ***@***.***> wrote: Yes! 👾 🎇 💖 Starting on this. Inserted 4.b) - ITK SpatialObject to VTK PolyData :-D — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#976 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAMMcsmA4AseshqonP5SZZznYJMa3Vp8ks5vLHq_gaJpZM4ZMLKj> .

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[thewtex]

@wschroed good point. We can take an incremental approach. First to PolyData so we can just visualize them. Then to VTK Implicit Functions. We likely find that we want / need the implicit functions for cropping, cutting, etc., but individual conversions will take more time. And, vtk.js Implicit Functions support can also mature in the process.

[thewtex]

#1 addressed here: InsightSoftwareConsortium/ITK-Wasm#190

[supriome]

Hi, @aylward @thewtex Any progress of UnstructuredGrid reader?

[finetjul]

@supriome technically you can support unstructured grid in vtk.js through itk.wasm. It's not easy (not well documented) but doable :-)

[thewtex]

Checked off step 2 per: https://kitware.github.io/vtk-js/examples/ItkWasmGeometry.html

[supriome]

@thewtex I finish an unstructured grid reader, then convert to polydata, use vtk.js vtkXMLPolyDataReader to render that file.
#2501 (comment)

[thewtex]

@supriome good work.

We did something similar a few refactoring generations ago in itk.js, but itk-wasm improves significantly the simplicity of the interface and performance.

[supriome]

Great, I'm looking forward to your final implementation, I realize that my implementation is definitely poor in terms of performance, but in order to achieve the functional requirements, this is the only way for now, if you have a better implementation, I will use your final solution

[skudev]

Hi, any progress on this? I would like to migrate my vtk.js project to use itk-wasm.js instead of itk.js. My project relies on itk/readPolyDataArrayBuffer to convert .vtu (unstructured grid) to vtp. Is this possible with itk-wasm.js? If yes, is there any documentation / example how to do this?

[thewtex]

Hi @skudev , I created a tracking issue here: InsightSoftwareConsortium/ITK-Wasm#1261