UBC Theses and Dissertations
An Object-oriented design for hierarchical B-spline surfaces Yan, Hailin
This thesis documents an object-oriented software system that supports free-form surface modelling based on the hierarchical overlay methodology of [Forsey88]. This work is motivated by the need to provide a space-efficient representation of tensor-product hierarchical spline surfaces, multiple offset method support, and general surface representation. This design uses a spatial data structure, the quadtree, to achieve this goal. The quadtree, itself a hierarchical data structure, is very suitable in this application because of its ability to focus on the interesting subsets of the data. This focusing results in an efficient representation. The quadtree is also attractive because of its conceptual clarity and ease of maintenance. The package is implemented in C++ to provide: a) extensibility so that the new tools can be easily integrated into the existing package; b) reusability of code; and c)localization of code. Finally, this object-oriented hierarchical design keeps all of the original features of the hierarchical overlay method of [Forsey90].
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