Automotive Body-in-White (BIW) is the term used to describe the framework of a vehicle body, minus the exterior panels and trim. The BIW typically includes the roof, floorpan, pillars, fenders, and headliner. In some cases, the BIW also includes the engine bay, trunk, and underbody. BIW construction generally begins with a combination of stamping, welding, and assembly processes. Stamping is used to create the various panels that make up the BIW, such as the roof, floorpan, and fenders. These panels are then welded together to form the basic structure of the vehicle body.