There are several publications on parting line determination. Tan et al. (1990)presented an approach by classifying all the part surfaces into visible and invisible surfaces for a given parting direction. The surface visibility is determined according to the surface orientation to the parting direction. The modified back face removal algorithm finally identifies the parting lines. Ganter and Skoglund (1993) proposed an approach to determine the parting lines of die-casting parts using a ‘rule set’ based on certain casting ‘rules of thumb’ and the part geometric properties. Besides, Weinstein and Manoochehri (1997) also presented their methodology to determine the parting lines for moulded parts and die-casting parts. In this research,the parting lines are determined as described in Nee et al. (1998), which classifies the moulding surfaces into different groups based on their geometric relationship to the parting direction and then generate the largest edge-loop in each surface group. The parting lines are identified based on proposed criteria.