Live version: https://ifcopenshell.github.io/wasm-preview/

This is a technological preview of an IfcOpenShell WASM python module for use in pyodide. It uses emscripten to compile the C/C++ (of the python interpreter, IfcOpenShell and its dependencies respectively) into a WebAssembly (WASM) module. WebAssembly can be used in the browser or other JavaScript runtimes such as NodeJS.

This approach of supporting IFC within the browser is rather heavy as it depends on a python interpreter loading the wasm-compiled monolithic IfcOpenShell wheel on demand. But nevertheless, we see this as the most powerful approach of enabling IfcOpenShell in the browser.

Over time, Python code has surpassed C++ as the predominant language in IfcOpenShell and has become the defacto standard for the IfcOpenShell API. We wouldn't want browser-based usage to require duplicating this powerful set of APIs.

Wrapping the full IfcOpenShell-python module results in a feature rich module, that makes for example, IFC validation, visualization, but also authoring a breeze because any pre-existing pure python module can be leveraged.

Allows direct usage of python objects in JavaScript code.

Example: https://github.com/IfcOpenShell/wasm-preview/blob/master/index.html#L99-L101

Allows running actual python code with the ability for JavaScript to easily reflect on global variables.

Example: https://github.com/IfcOpenShell/wasm-preview/blob/master/index.html#L114-L117

Allows running inline python code in HTML script tags

• Performance of loading and running code is not optimal.
• C++ exception handling in the IfcOpenShell dependencies seems to cause issues in WASM.

The overall IfcOpenShell roadmap of modularizing the geometry libraries, providing alternative implementations (CGAL, Eigen) and providing a more plug-in like interface will alleviate most of the issues WASM-IfcOpenShell users will experience as emscripten can load shared libraries on demand.

Stay tuned!