An expert process planning and fixturing system has been developed. The system employs forward planning strategy, i.e. it begins with the blank part and applies operations for each face/feature until it reaches the finished part model. After each operation the machined region is removed and a new intermediate model is generated. A part model description scheme called face-oriented neighbouring graph has been utilized to represent blank, finished and intermediate models within the database. This paper is focused on intermediate part modelling within the process planning system. Copyright (C) 1996 Elsevier Science Ltd.