anchor.diff:  	DegAngle = deg2rad(Angle),
   	from_axis_angle(radians, {_, _, _} = Axis, DegAngle).
   
  -% -------------------------------------------------------------------------
  +% ---------------------------------------------------------------------------------------------------------------------
   
   %% @doc Converts from body rates (radians) to a quaternion.
   from_body_rates({_, _, _} = Vec) ->
  
positive.code: 		ok -> ok
  	end.
  
  % -------------------------------------------------------------------------
  
  -define(NORMALIZED_TOLERANCE, 0.0000001).
  -define(IDENTITY, {1, 0, 0, 0}).
  
  % -------------------------------------------------------------------------
  
  -include("log.hrl").
  
  %% ------------------------------------------------------------------------
  %% External API
  %% ------------------------------------------------------------------------
  
  %% @doc Convert from a quaternion to a list
  quat_to_list({W, X, Y, Z}) ->
  
negative.code: 	Unit = vector:unit({X, Y, Z}),
  	from_axis_angle(Unit, OriginalRotation * Factor).
  
  % ---------------------------------------------------------------------------------------------------------------------
  
  %% @doc Returns the squared length of the quaternion. This is useful in some optimization cases, as it avoids a sqrt call.
  squared_norm({W, X, Y, Z}) ->
  