“…Most of the feature recognition systems developed up to today are solid modeller dependent, and are either CSG-based or B-rep-based systems. The systems developed by Woo (1982), Woodwark (1988), Perng et al (1990), Sakurai and Chin (1993), Kim (1994), and Parry- Barwick and Bowyer (1995) are examples of the ® rst category, whereas systems developed by Kyprianou (1980), Henderson (1984), Joshi and Chang (1988), Sakurai and Gossard (1988), Vandenbrande and Requicha (1990), Hwang (1991), Prabhakar and Henderson (1992), Tseng and Joshi (1994), Chan (1994), Sakurai (1995), Gu et al (1995), and Nezis and Vosniakos (1997) are based on B-rep models.…”