helmertMetersFromParameters builds the helmert transformation as a
meter-input/meter-output 4x4 directly from parsed parameters, bypassing
autoLocal2Global's normalisation step. This preserves
IfcMapConversionScaled.FactorX/Y/Z in the rotation block so the factor
applies to placement translations when the matrix is precomputed
per-model and composed with placements at upload time. For ordinary
IfcMapConversion (factor = 1) this is bit-identical to
autoLocal2Global; only diverges on rare surveyed models with non-unit
factors, where it is the only correct behaviour.
getMapUnit returns IfcCoordinateOperation.TargetCRS.MapUnit so callers
can resolve the unit-to-metres scale via Unit.h's siScaleFromNamedUnit.
autoLocal2Global is unchanged — kept as a clean port of the python
ifcopenshell.util.geolocation reference impl for one-shot
project-units-in / map-units-out callers.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Mirrors ifcopenshell.util.geolocation: HelmertTransformation parameters
(IfcMapConversion / IfcMapConversionScaled / IfcRigidOperation, plus
IFC2X3 ePSet_MapConversion), get_wcs from IfcGeometricRepresentationContext,
local2global, and auto_local2global. Lives in src/ifcviewer/ for now;
will move out when ifcopenshell.util is ported to C++.
Not yet wired into the streamer. A subsequent commit fixes the
unit handling for the iterator's meter-by-default output.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Dion Moult