Rick

And a follow up question... which schema is the most current 4x3 tr1 or 4x3 add1? What's the difference between tr1 and add1?

I've been away from IfcOpenShell for a while and finally have the time to get back to work on generating IFC models for bridges. Which branch should I be using? 0.6, 0.7, 0.8. A lot of my code broke when attempting to build against 0.7. That's ok because it looks like the changes are a big improvement.

Thanks for the clarification. It seems alignment->Nests() would be right because I want to know what is nested inside the alignment. Since alignment->IsNestedBy() is correct, then I'll update my brain. Very interesting about the file. I pulled it from bSI-InfraRoom/IFC-infra-unit-test on github. How do you dump the schema validation errors?

The attached file uses IfcRelNests to relate IfcAlignmentHorizontal and IfcAlignmentVertical to IfcAlignment (this format began with 4x3 rc2). When extracting data from the model, IfcAlignment->Nests() returns an empty container. Here is sample code and the file I'm trying to read. Thanks int main(int argc,char** argv) { // Redirect the output (both progress and log) to stdout Logger::SetOutput(&std::cout, &std::cout); // Parse the IFC file provided in argv[1] IfcParse::IfcFile file(argv[1]); if...

The problem was the express file. It copied to my computer as HTML. Sorry to waste your time - I didn't think to check that. I got a file from bSI and now the code generate is working. For the next step, should I take the Ifc4x3_rc3.h/cpp and other generated files, move them to the IfcParser folder, add them to the VisualStudio project and build?

Thomas - I'm trying to generate parsing code for the IFC4x3 RC3 and RC4 specification. The express_parser.py script is producing errors as shown below. I've copied the EXP file into the ...\express folder so I don't think it's an input\path issue. Any suggestions? I've verified I'm using python 3.9.0 and pyparsing is installed (import pyparsing does not generate errors) PS F:\IfcOpenShell\src\ifcopenshell-python\ifcopenshell\express> python express_parser.py IFC4x3_RC3.exp header implementation schema_class...

Thanks for the feedback. I'll update my application to use the safer code. I thought bSI had a rigorous compliance certification process. I would think it would detect problems like I came across and withhold certification.

I think I found a solution. An IfcParse::IfcInvalidTokenException gets thrown because the IFCLENGTHMEASURE token is expected but it was not provided. So, I can catch the exception and then extract the value "manually". double conversion_factor = -1; try { auto value_component = measure_with_unit->ValueComponent(); //<--- Throws exception here conversion_factor = *(value_component->as<IfcSchema::IfcLengthMeasure>()); } catch (IfcParse::IfcInvalidTokenException& e) { Argument* pArgument = measure_with_unit->get("ValueComponent");...