anchor.diff:  		first_defined(UpdateX, CurrentX),
   		first_defined(UpdateY, CurrentY),
   		first_defined(UpdateZ, CurrentZ)
  -		}.
  +	}.
   
   %% --------------------------------------------------------------------------------------------------------------------
   
  
positive.code: 	Orientation = pre_physics_rk4:get_prop(orientation, Physical),
  	PositionVelAbs = pre_physics_rk4:get_prop(linear_velocity, Physical),
  	AngularVelAbs = pre_physics_rk4:get_prop(angular_velocity, Physical),
  
  	ShipState = dict:fetch(ship, Entity#entity.state),
  	{TX, TY, TZ} = dict:fetch(target_linear_velocity, ShipState),
  
negative.code: %% --------------------------------------------------------------------------------------------------------------------
  
  simulate(Entity, EntityEngineState) ->
  	{ShipUpdate, Entity1} = do_flight_control(Entity),
  	PhysicalResult = entity_physical:simulate(Entity1, EntityEngineState),
  
  	case PhysicalResult of
  		{undefined, Entity2} ->
  			{ShipUpdate, Entity2};
  		{PhysicalUpdate, Entity3} ->
  			case ShipUpdate of
  				undefined ->
  					{PhysicalUpdate, Entity3};
  				_ ->
  					{ShipUpdate ++ PhysicalUpdate, Entity3}
  			end
  	end.
  
  %% --------------------------------------------------------------------------------------------------------------------
  
  