The effective reuse of freeform features represented by NURBS is still an open issue. In this paper, a novel approach to the reuse of freeform features with NURBS representation is proposed. Firstly, the conditions for preserving differential properties of reused freeform features are derived, and a reuse-oriented representation of freeform features is put forward. Based on them, a reuse algori...

This paper proposed a new approach for optimum path planning in 2D environments cluttered with static obstacles. The presented model consists of four steps.In the first step, the skeleton of free obstacles space is extracted. The thin lines are converted into a graph in the second step. the determination of shortest length trajectory is done in the third step. The last step is consacred to cons...

This paper presents an accurate and efficient method to solve both point projection and point inversion for NURBS curves and surfaces. We first subdivide the NURBS curve or surface into a set of Bézier subcurves or patches. Based on the relationship between the test point and the control polygon of Bézier curve or the control point net of the Bézier patch, we extract candidate Bézier subcurves ...

Isogeometric analysis, as a special field of the finite element method (FEM) which integrates geometric and finite element mesh modelling, is one of the promising directions of FEM development. The paper presents a concept of isogeometric FEM analysis of thin-walled structures based on the Kirchhoff-Love shell formulation and NURBS as basis functions. The basic properties of isogeometric shell ...

A Reissner-Mindlin shell formulation based on a degenerated solid is implemented for NURBS-based isogeometric analysis. The performance of the approach is examined on a set of linear elastic and nonlinear elasto-plastic benchmark examples. The analyses were performed with LS-DYNA, an industrial, general-purpose finite element code, for which a user-defined shell element capability was implement...

In this paper we present an algorithm for planning the path of a 3 DOF mobile platform for a humanoid robot. It is simple enough to be executed online and yet powerful enough to generate a smooth path from starting point and orientation to a destination point with a different orientation. Thus we strive to achieve a human-like appearance of our robot that encourages the humans in vicinity to in...

NURBS surfaces are among the most commonly used parametric surfaces in CAGD and Computer Graphics. This paper investigates shape modi®cation of NURBS surfaces with geometric constraints, such as point, normal vector, and curve constraints. Two new methods are presented by constrained optimization and energy minimization. The former is based on minimizing changes in control net of surfaces, wher...

In this paper, we present an approach that extends isogeometric shape optimization from optimization of rectangular-like NURBS patches to the optimization of topologically complex geometries. We have successfully applied this approach in designing photonic crystals where complex geometries have been optimized to maximize the band gaps. Salient features of this approach include the following: 1)...