Herman, I.Reviczky, J.2014-10-212014-10-2119881467-8659https://doi.org/10.1111/j.1467-8659.1988.tb00628.xThe modelling clip as proposed for example in PHIGS is mathematically analyzed and a method to perform it is proposed. The method has the particular edvantage of avoiding all possible singularities appearing in the course of a projective transformation. Additionally, further optimizations in the implementation of the whole output pipeline are proposed.10.1111/j.1467-8659.1988.tb00628.x265-271