Do the DAE / COLLADA specifications allow for these “custom” attributes ?
(Usual XML formats must follow their schema.)
Looking at the v1.4 spec I see that there IS provision for an <extra> element.
(See “Extensibility”, page 36.)
But attaching an attribute dictionary named “extra” or “dae” (with a “direction” attribute whose value is “North”) to a SketchUp face within a group, fails to export to the DAE file as any attribute.