Function same_components 

pub fn same_components(a: &[f64], b: &[f64], epsilon: Option<f64>) -> bool

IfcSameCartesianPoint / IfcSameDirection over raw component lists.

Both schema functions have identical bodies apart from the attribute they read, so they share one implementation. A missing third component reads as zero: the schema initialises cp1z/dir1z to 0 and only overwrites when SIZEOF > 2, which makes a 2D point equal to its 3D lift.