Concurrent engineering (CE) is a methodology applied to product lifecycle development so that high quality, well designed products can be provided at lower prices and in less time. Many research works have been proposed for efficiently modeling of different domains in CE. However, an integration of these works with consistent data flow is absent and still in great demand in industry. In this paper, we present a generic integration framework with a semantic feature model for knowledge representation and reasoning across domains in CE. An implementation of the proposed semantic feature model is presented to demonstrate its advantage in knowledge representation by feature transformation across domains in CE.

In this paper, we present a semantic feature language for knowledge representation and reasoning across different domains in concurrent engineering (CE). The proposed language utilizes a feature model which is depicted in two levels. First a unified and formal framework is presented for semantic features in CE. The presented semantic features are general and a feature formal language is used to characterize the engineering data in multi-discipline domains at the most abstract level. At the details level, the general semantic features are realized in a hierarchical manner with the aids of object-oriented programming. A preliminary implementation of the proposed semantic feature model is also presented.

In this paper, a new canonical model of virtual human head is presented. By using a uniform two-step refinement operator, the canonical model has a natural multiresolution structure. In the coarsest level, the canonical model is represented by a control mesh M0which serves as the anatomical structure of the head. To achieve fine geometric details over M0, a multi-level detail set is assigned to the corresponding control vertices in M0, with the aid of a uniquely defined local frame field. Compared to the previously work, the proposed canonical model not only captures the physical characteristics of the head, but also is optimal in the geometric sense. Diverse examples are presented, showing that the deformed model is smooth and the presented canonical model is easy to use.

As compatible meshes play important roles in many computer-aided design applications, we present a new approach for modelling compatible meshes. Our compatible mesh modelling method is derived from the skin algorithm [Markosian et al. 1999] which conducts an active particle-based mesh surface to approximate the given models serving as skeletons. To construct compatible meshes, we developed a duplicate-skins algorithm to simultaneously grow two skins with identical connectivity over two skeleton models; therefore, the resultant skin meshes are compatible. Our duplicate-skins algorithm has less topological constraints on the input models: multiple polygonal models, models with ill-topology meshes, or even point clouds could all be employed as skeletons to model compatible meshes. Based on the results of our duplicate-skins algorithm, the modelling method of n-Ary compatible meshes is also developed in this paper.

In this paper the applications of equilibrium equation to geometric modeling is exploited and efficient numerical algorithms are proposed for solving the equilibrium equation. First we show that from diverse geometric modeling applications the equilibrium system can be extracted as the central framework. Second, by exploiting in-depth the special structures inherent in the geometric applications, we present simplified analytic solutions to the resulting geometric equilibrium equations via system decomposition. Finally, given the observation that the geometric equilibrium systems are extremely sensitive to both perturbations in input data and round off errors, efficient, stable and accurate numerical algorithms are proposed.

In this paper, paper we present a coherence‐based method to detect collisions between the garment and human model for dressed human simulations. Based on the property of coherence, collisions can be rapidly detected by tracking the movement of the most likely geometric elements to collide. The voxel technique is employed to quickly identify the potential collision region. Experimental results show that our method is very efficient.

Cloth draping is of particular interest in the field of garment engineering. Most cloth draping simulation stresses the visual effects of garment design. However, the accuracy of the draping effect should not be overlooked, particularly for garment manufacturing. The accuracy of the draping behaviour is largely affected by the fabric properties. This paper discusses the issue of incorporating the fabric properties into the cloth model, so that its draping behaviour can be realistically simulated. These fabric properties are expressed in terms of a set of measurable mechanical properties. The draping behaviour of the cloth is derived based on elastic theory. Dynamic draping simulation is presented with illustrative examples.

We present a voxel-based collision detection method for clothed human animation. We speed up the performance of the voxel-based method by choosing an appropriate voxel size and using a fast voxelization approach. Based on the voxel method, we propose a self-collision detection method and a simplified collision detection method. First, the efficiency of self-collision detection is improved by taking advantage of the curvature and multi-layer methods. Second, the efficiency of cloth/human collision detection is improved by introducing auxiliary line segments. Some heuristics are provided to further increase the efficiency of collision detection. Experimental results demonstrate that our method is efficient for clothed human animation.

This paper presents a general method for transformations of an object between 2D and 3D which can be used efficiently in computer-aided garment design. A uniform triangular spring–mass-based deformable model is employed. Both 2D-to-3D and 3D-to-2D transformations can be implemented in the same model. An efficient collision detection method is also discussed. © 1998 John Wiley & Sons, Ltd.