Publications / 1987 Proceedings of the 4th ISARC, Haifa, Israel

An Integrated Approach to Geometric Modelling

Yehuda E. Kalay
Pages 447-457 (1987 Proceedings of the 4th ISARC, Haifa, Israel, ISSN 2413-5844)
Abstract:

Solid modelling has been recognized as a powerful computer-aided design tool, being informationally complete and semantically well-formed. However, it is insufficient by itself to support the design process of complex artifacts such as buildings, since it lacks the abstraction properties provided by computer-aided drafting tools. This paper presents an integrated approach to geometric modelling that combines the power of solid modelling with the intuitive design and communication capabilities of drafting. Integration is achieved by representing the designed artefact non-redundantly in a 3-dimensional WORLD, and manipulating it through multiple 2-dimensional VIEWs. The WORLD consists of a collection of shaped that store all the formative information pertinent to the designed artefact, while the VIEWs consist of images of selected shapes generated through particular two-way mapping transforms. Simultaneous display of several VIEWs that depict the same set of shapes through different transforms enables addressability of points in the 3-dimensional WORLD. The shapes are represented by a data structure based on the hybrid edge model, which facilitates the integration of points, lines, polygons, and solids in one formative hierarchy. VIEWs reference the formative entities in the database, and include design and communication aids (e.g. – dimension lines, construction lines, annotations and graphic symbols) to enhance the visual content of the images without encumbering the representation of the shapes themselves. Modifications that are applied to the shapes through any VIEW are immediately apparent in all other VIEWs in which the shapes are imaged. The integration of drafting and modelling simplifies the use of powerful modelling utilities by designers, facilitates communicating the results of the design process, and enhances the integrity of the designed artifact.

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