A new method for 3-D shape registration of prismatic objects is presented. The term prismatic object denotes any object with sharp boundaries on its surface. These kinds of objects cannot be correctly registered with typical existing methods, which require smooth overlapping of the whole surface. The method presented here is based on the use of reference marks, placed on a planar glass plate that is attached to the prismatic object. Two 3-D range measurements of the object are then acquired, before and after rotating the object by approximately 180 deg. Using the reference marks on the glass and two different calibrations of the 3-D range scanning system, these two range measurements can be correctly merged to provide a full 3-D range scan of the prismatic object.