I doesn't work for me with Add-in version 2020.2.0.48 but it does work with a colleague using Add-in version 2020.1.0.1. Export using the same Revit file that works with him does not work with me.
This is what I did in C++ https://gist.github.com/stefkeB/e2b308e13d299328ecd1dc8db2d20cc5#file-main-cpp I'm now converting the code to branch v0.6.0 which is a bit different from the methods in v0.5.0, alas.
Tricky, as iOS requires static libraries to be compiled in. This also applies to all dependencies of IfcOpenShell (OpenCASCADE is the biggest one at that).
Is it possible to support both IFC2x3 and IFC4 when building? The IfcConvert downloadable binary does seem to work with both, but my own compilation seems to work only for one scheme (or did I do something wrong?)
Any new info? We are working to standardize BIM usage and having all these material properties which don't get exported to IFC is quite a limitation.