CAD systems are still evolving, using new dialog approaches and improving models (features, functional modeling, knowledge management ...). The integration of the different software (CAD, simulation, CAM ...) is in many cases artificial. We describe in this paper an application whose goals are the following: (1) define a trade oriented intuitive man-machine dialog ; then a knowledge-based engineering methodology is implemented.; (2) use a Web-based architecture in order to be accessible from any computer, being sure to get the up to date version and permitting to distribute it on the adequate computers. This article will present the overall concepts, models and methods used. Our study relates to the possibility of using the knowledge of an expert in modeling using scripts and to implement a distributed system.