Computers

  2010 SEP 2 - (VerticalNews.com) -- "This paper depicts a new CAT (Computer Aided Tolerancing) system called Quick GPS (Geometrical Product Specification), for assisting the designer when specifying the functional tolerances of a single part included in a mechanism, without any required complex function analysis. The mechanism assembly is first described through a positioning table formalism," scientists in Cachan, France report.

  "In order to create datum reference frames and to respect assembly requirements, an ISO based 3D tolerancing scheme is then proposed, thanks to a set of rules based on geometric patterns and TTRS (Technologically and Topologically Related Surfaces). Since it remains impossible to determine tolerance chains automatically, the designer must impose links between the frames. The CAT system that we developed here proposes ISO based tolerance specifications to help ensure compliance with the designer's intentions, saving on time and eliminating errors. This paper will detail both the set of tolerancing rules and the designer's approach," wrote B. Anselmetti and colleagues ...read more

  2010 SEP 2 - (VerticalNews.com) -- "The identification of C-1 continuities is important in many applications involving point clouds or triangular meshes, such as surface segmentation, inspection and rendering. The methods in literature have some limitations which make them strongly dependent on some properties of the mesh (point typology, mesh resolution, uniformity of the shape of triangles and error in point location)," scientists in Italy report ...read more

  2010 SEP 2 - (VerticalNews.com) -- According to a study from Iran, "Voronoi diagrams have useful applications in various fields and are one of the most fundamental concepts in computational geometry. Although Voronoi diagrams in the plane have been studied extensively, using different notions of sites and metrics, little is known for other geometric spaces."

  "In this paper, we are interested in the Voronoi diagram of a set of sites in the 3D hyperbolic upper half-space. We first present some introductory results in 3D hyperbolic upper half-space and then give an incremental algorithm to construct Voronoi diagram. Finally, we consider five models of 3D hyperbolic manifolds that are equivalent under isometries," wrote Z. Nilforoushan and colleagues ...read more