Method get_pose

dm_control/composer/entity.py:417–453

Get the position and orientation of this entity relative to its parent. Note that the semantics differ slightly depending on whether or not the entity has a free joint: * If it has a free joint the position and orientation are always given in global coordinates. * If the enti

(self, physics)

          xmat.shape))

  def get_pose(self, physics):
    """Get the position and orientation of this entity relative to its parent.

    Note that the semantics differ slightly depending on whether or not the
    entity has a free joint:

    * If it has a free joint the position and orientation are always given in
      global coordinates.
    * If the entity is fixed or attached with a different joint type then the
      position and orientation are given relative to the parent frame.

    For entities that are either attached directly to the worldbody, or to other
    entities that are positioned at the global origin (e.g. the arena) the
    global and relative poses are equivalent.

    Args:
      physics: An instance of `mjcf.Physics`.

    Returns:
      A 2-tuple where the first entry is a (3,) numpy array representing the
      position and the second is a (4,) numpy array representing orientation as
      a quaternion.

    Raises:
      RuntimeError: If the entity is not attached.
    """
    root_joint = mjcf.get_frame_freejoint(self.mjcf_model)
    if root_joint:
      position = physics.bind(root_joint).qpos[:3]
      quaternion = physics.bind(root_joint).qpos[3:]
    else:
      attachment_frame = mjcf.get_attachment_frame(self.mjcf_model)
      if attachment_frame is None:
        raise RuntimeError(_NO_ATTACHMENT_FRAME)
      position = physics.bind(attachment_frame).pos
      quaternion = physics.bind(attachment_frame).quat
    return position, quaternion

  def set_pose(self, physics, position=None, quaternion=None):
    """Sets position and/or orientation of this entity relative to its parent.