A process and apparatus for forming customized footwear, such as shoes, boots or inner bladders for shoes or boots, and particularly an athletic shoe or boot, is disclosed in which an impression of the foot is used to make a positive mold, around which the shoe, boot or bladder is constructed. In the improved process a range-of-motion measuring apparatus is used to accurately determine the neutral position of the bone structure of the rearfoot complex of the foot. The foot is maintained in that position by means of the apparatus while the impression or casting of the foot is being made. The process provides a shoe, boot or inner liner or bladder therefor which will evenly support the foot in a neutral position. The range-of-motion measuring apparatus includes a beam generating laser that is directed toward a mirror mounted on the leg of the person being fitted. The mirror, in turn, is directed to reflect the laser beam onto a measuring device, such as a scale, which can be used to electronically or visually measure leg rotation during pronation and supination of the foot and, accordingly, to position the bone structure of the foot in its neutral position.