An intake or exhaust port molding core of a cylinder head includes a plurality of protruders on the core to form a plurality of depressed grooves in the intake or exhaust port during casting of the cylinder head. The scan driving unit releases the scanning unit retained by the retaining unit, and drives it when the first force is larger than the second force. The venting system can provide air flow around in wall obstacles by channeling in air from the outside or carrying air around the obstacle from within the wall or roof itself. When the process returns to the state, fragment validation has reached successful completion.