.. default-domain:: py
.. highlight:: py
.. currentmodule:: SpaceCenter

ReferenceFrame
==============


.. class:: ReferenceFrame

   Represents a reference frame for positions, rotations and
   velocities. Contains:

   * The position of the origin.
   * The directions of the x, y and z axes.
   * The linear velocity of the frame.
   * The angular velocity of the frame.

   .. note::

      This class does not contain any properties or methods. It is only
      used as a parameter to other functions.

   .. staticmethod:: create_relative(reference_frame, [position = (0.0, 0.0, 0.0)], [rotation = (0.0, 0.0, 0.0, 1.0)], [velocity = (0.0, 0.0, 0.0)], [angular_velocity = (0.0, 0.0, 0.0)])

      Create a relative reference frame. This is a custom reference frame
      whose components offset the components of a parent reference frame.

      :param ReferenceFrame reference_frame: The parent reference frame on which to base this reference frame.
      :param tuple position: The offset of the position of the origin, as a position vector. Defaults to :math:`(0, 0, 0)`
      :param tuple rotation: The rotation to apply to the parent frames rotation, as a quaternion of the form :math:`(x, y, z, w)`. Defaults to :math:`(0, 0, 0, 1)` (i.e. no rotation)
      :param tuple velocity: The linear velocity to offset the parent frame by, as a vector pointing in the direction of travel, whose magnitude is the speed in meters per second. Defaults to :math:`(0, 0, 0)`.
      :param tuple angular_velocity: The angular velocity to offset the parent frame by, as a vector. This vector points in the direction of the axis of rotation, and its magnitude is the speed of the rotation in radians per second. Defaults to :math:`(0, 0, 0)`.
      :rtype: :class:`ReferenceFrame`
   

   .. staticmethod:: create_hybrid(position, [rotation = None], [velocity = None], [angular_velocity = None])

      Create a hybrid reference frame. This is a custom reference frame
      whose components inherited from other reference frames.

      :param ReferenceFrame position: The reference frame providing the position of the origin.
      :param ReferenceFrame rotation: The reference frame providing the rotation of the frame.
      :param ReferenceFrame velocity: The reference frame providing the linear velocity of the frame.
      :param ReferenceFrame angular_velocity: The reference frame providing the angular velocity of the frame.
      :rtype: :class:`ReferenceFrame`
   

      .. note::

         The *position* reference frame is required but all other
         reference frames are optional. If omitted, they are set to the
         *position* reference frame.