This International Standard defines the maximum material requirement, the least material requirement, the reciprocity requirement and specifies their applications. The use of these requirements is to control specific functions of workpieces where there is a mutual dependence of size and geometry, for fulfilling the function assembly of parts (for maximum material requirement) and e.g. for fulfilling the function minimum wall thickness (for least material requirement). However the maximum material requirement and least material requirement may be used to fulfill other functional design requirements.