Hubl, JosefHerman, Ivan2014-10-212014-10-2119901467-8659https://doi.org/10.1111/j.1467-8659.1990.tb00383.xThe modedling clip of the PHIGS ISO Standard is mathematically analysed. The most important result of this analysis is the fact that the projective image of a modding clip body (that is a not necessarily bounded convex body in space) is simply the union of two convex bodies. Furthermore, it will also be proved that in some cases one of these two bodies is empty. This fact makes the implementation of the modelling clip fairly straightforward and makes it also possible to use all already existing results on clipping against general convex bodies without change.10.1111/j.1467-8659.1990.tb00383.x101â 107