Why does IfcRigidOperation support IfcPlaneAngleMeasure

[Moult]

The usecase of IfcRigidOperation is to do a simple translation from A to B, most commonly when you truncate large coordinates.

Yet FirstCoordinate and SecondCoordinate allow IfcPlaneAngleMeasure... but why? Lat longs (i.e. angle measures) are very small numbers anyway which seem as though you'd never need to transform them, and the usage of another unit type complicates matters (default unit of angle measures ... radians / degrees?) and mixing of unit types between object placements which are IfcLengthMeasure + IfcPlaneAngleMeasure = ?

I'm a little surprised and confused on how to implement this. It looks as though it'll just create a lot of confusion for users.

[Moult]

I should probably mention that Scale doesn't exist on IfcRigidOperation. This makes the behaviour inconsistent and ambiguous as to how to handle IfcLengthMeasure.

[aothms]

@pjanck any feedback?

[pjanck]

Hi @Moult - please consult my paper titled "Georeferencing of IFC Geometries" from this years 20. Ingenieursvermessungskurs and try it out yourself with these instructions. I'm happy to support you implementing IfcRigidOperation during Ifc-for-Tunneling support calls as denoted here.

[Moult]

@pjanck why is the Scale attribute omitted for IfcRigidOperation?

How do you handle mixing of unit types between object placements which are IfcLengthMeasure + IfcPlaneAngleMeasure = ?