Error rendering model

[joaomlap]

Hi,

Not sure if this is helpful at all but while following the steps here:
https://www.kitware.com/vtk-wasm-and-its-trame-integration/

I was able to render some parts of my big-ish model but when trying to render the full thing I got some errors:

Python Server:

 JS Error => 2024-10-29 16:11:06.364 (  78.142s) [          401734]vtkGenericDataArray.txx:378    ERR| vtkTypeInt64Array (0xffe85080): Unable to allocate 476064 elements of size 8 bytes.
 JS Error => WASM update failed
 JS Error => RuntimeError: null function or function signature mismatch

Browser console;

2024-10-29 16:27:10.215 (  76.527s) [          401734]vtkGenericDataArray.txx:378    ERR| vtkTypeInt64Array (0xffe850e8): Unable to allocate 476064 elements of size 8 bytes. 
overrideMethod @ hook.js:608
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hook.js:608 WASM update failed
overrideMethod @ hook.js:608
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trame_vtklocal.umd.js:1 4293415576
hook.js:608 RuntimeError: null function or function signature mismatch
    at vtkWasmSceneManager.wasm:0xa84d04
    at vtkWasmSceneManager.wasm:0xfbdd5a
    at dynCall (vtkWasmSceneManager.mjs:9:73159)
    at vtkWasmSceneManager.mjs:9:73240
    at Object.startEventLoop (eval at newFunc (vtkWasmSceneManager.mjs:9:68337), <anonymous>:8:10)
    at trame_vtklocal.umd.js:1:7497

[jourdain]

Can you describe the geometry in question? Multi-block, number of blocks, number of cells, number of points...
Just so we have some idea of what you are talking about in term of big-ish model?

[jspanchu]

@joaomlap I think your mesh is really big. The error basically says that VTK failed to allocate almost 3.6 GB for cell array connectivity (or offsets in a vtkCellArray because the data type is vtkTypeInt64Array) Since the memory limit in wasm32 is 4GB it is quite easy for applications to run out of memory. I guess the extra 400 megabytes were either used up for the points of your mesh or for small allocations internal to VTK used to store the state/blobs in C++ object manager memory.

@jourdain We need a way for trame to optionally use wasm64.

[jourdain]

Yes we will enable such option once wasm64 is more widely supported

[joaomlap]

Hi all, just a question, not specifically on this issue (which is still active), but if the user is running the server on his machine, won't this double the memory usage on his computer?
Because it's being held in the server, serialised and then rendered again in the frontend right?
Should I be doing something different to prevent this?
Would something like tauri/electron help because we could read directly from disk to our (embedded) wasm modules?

[jourdain]

The server should not do the rendering, only the client with WASM. You do have some memory usage duplication, but not as much as your original mesh if it has 3D cells. Also the memory allocation is limited in the browser, but not really (except due to hardware limit) on the server. Doing tauri/electron, will not reduce the memory usage as it does not remove the server.

[jspanchu]

WASM64 is available since:

1. Chrome 133 (Feb 2025)
2. Firefox 134 (Jan 2025)
3. Node.js 24.0 (May 2025)

@jourdain safari is the only browser that does not support it yet.