Extracting Geometry from an IFC File

Use when extracting the geometry of an IFC element from an existing file in order to render it, mesh it, or measure it: resolving IfcProduct.Representation to its shape items, picking the right representation, walking the IfcLocalPlacement chain to a world transformation matrix, and decoding each RepresentationType (SweptSolid, Brep, Tessellation, CSG/Clipping, MappedRepresentation).