A rational and comprehensive approach for indicating when cesarean delivery (C/S) is necessary would result in a limitation in the overall maternal risks of childbirth as well as in the cost of health care. For this purpose, we are in the process of developing a set of computer aided design (CAD) models and a systematic and flexible simulation of the birth process. Different from the volume-based approach, our system provides three dimensional surface models of 1) the maternal bony pelvis obtained from digital radiographic images of computed tomographic (CT) pelvimetry and 2) fetal anatomy obtained from ultrasound images. Our modelling system and initial simulations bear many similarities to the results of assembly/disassembly planning research in robotics. Our initial result on generating the detailed CAD surface models is reported in this paper.