Abstract: Computer-aided design (CAD) systems have become parametric, basing shape design on constraints and design feature operations. We review the development of constraint-based parametric CAD, explaining ...

Abstract: Geometric computation software tends to be fragile and fails occasionally. This robustness problem is rooted in the difficulty of making unambiguous decisions about incidence and nonincidence, ...

Abstract: Early constraint solvers used propagation techniques that were inadequate for solving simultaneous constraint problems. Simultaneous problems, also called variational problems, require solving systems ...

Abstract: With parametric computer-aided design (CAD) software, designers can create geometric models that are easily updated (within limits) by modifying the values of controlling parameters. These numeric ...

Abstract: The writers report on a simulation study of the performance of the North Tower (WTC-I) of the World Trade Center complex during the impact of American Airlines Flight 11 on September 11, 2001. We discuss impact damage that ...