Physics3D/Charges/MateConnector.openplx
MateConnector

MateConnector is Physics.Charges.Charge:
    with Signals.MateConnector.MCLinearVelocity3DOutputTrait
    with Signals.MateConnector.MCAngularVelocity3DOutputTrait
    .doc: """
The MateConnector has a implicit frame defined from two orthogonal vectors local to the owning model.
The two vectors are named main_axis and normal and they must span a plane in 2D. If the normal is not specified
OpenPLX computes an orthogonal normalized vector to the main_axis.
The purpose of the main_axis is to act as the direction of an interaction that is used as e.g. the rotational dof of a hinge,
translational dof of a prismatic, or the normal axis of a planar constraint. The purpose of the normal axis is to define the two
orthogonal directions (binormal = main_axis x normal).

If the model require parametrisation in any direction orthogonal to the main_axis,
or if you model something like the hands on the clock, you like for example the default zero position
to point to twelve aclock, you make sure the normal axis of the MateConnector on the clock point towards twelve.

Physics3D has the concept of a reference mate connector at the origin.

"""

    position is Math.Vec3
    # User set direction, which is the main_axis mate direction
    # E.g. it will define the hinge axis with respect to the MateConnector frames
    main_axis is Math.Vec3: # Defaults to the z-axis
        z: 1
    # A non parallel vector to main_axis axis
    normal is Math.Vec3: main_axis.get_orthogonal_unit_vector()