In a large-scale design process, designers cooperate in a complex situation where a Variety of software tools run on different hardware platforms. This paper presents a data enhancement approach to integrate heterogeneous Computer-Aided Design (CAD) databases through the Internet. The data enhancement means topological changes in a geometric model and additional information in design semantics. The geometric data is enhanced using a non-manifold modeler to produce data sets valuable in downstream applications such as a Finite Element Method (FEM) solver or a detail design system. As a practical example, a shipbuilding product model database has been implemented based on the Standard for the Exchange of Product (STEP) model data methodology and shipbuilding features. The system has been implemented on a network environment that consists of a Web browser, Common Object Request Broker Architecture (CORBA) objects, a relational database management system, a data enhancement module, and various computer-aided applications. (C) 2000 Elsevier Science B.V. All rights reserved.