RPYOutput is Physics.Signals.Output:
    .doc: """
A Roll Pitch Yaw output given an interaction.
For interactions where it is unambiguous which position is requested,
the output will give the current value.
"""
    type: Physics.Signals.InputOutputType.RPY
    source is Physics3D.Signals.RPYOutputTrait
    marshalling:
        r is Physics.Signals.RealField
        p is Physics.Signals.RealField
        y is Physics.Signals.RealField
