Abstract: A forming leveller establishes one or more datum or reference planes in variable thickness stock to facilitate subsequent roll forming. The reference planes may be established on the same side or opposite sides of the stock with a lateral gap to facilitate transition forming. The leveller includes top and bottom closely spaced roll sets forming multiple passes mounted on bottom and top frames, respectively, with floating rolls being opposed to fixed rolls. Back-up rolls are provided for the floating rolls and pressure devices urge the floating rolls against the stock in turn against the fixed rolls to form the desired reference planes thus enabling complex shapes to be roll formed from the variable thickness stock.