Interactive inspection of complex multi-object industrial assemblies

The final publication is available at Springer via http://dx.doi.org/10.1016/j.cad.2016.06.005The use of virtual prototypes and digital models containing thousands of individual objects is commonplace in complex industrial applications like the cooperative design of huge ships. Designers are interested in selecting and editing specific sets of objects during the interactive inspection sessions. This is however not supported by standard visualization systems for huge models. In this paper we discuss in detail the concept of rendering front in multiresolution trees, their properties and the algorithms that construct the hierarchy and efficiently render it, applied to very complex CAD models, so that the model structure and the identities of objects are preserved. We also propose an algorithm for the interactive inspection of huge models which uses a rendering budget and supports selection of individual objects and sets of objects, displacement of the selected objects and real-time collision detection during these displacements. Our solution–based on the analysis of several existing view-dependent visualization schemes–uses a Hybrid Multiresolution Tree that mixes layers of exact geometry, simplified models and impostors, together with a time-critical, view-dependent algorithm and a Constrained Front. The algorithm has been successfully tested in real industrial environments; the models involved are presented and discussed in the paper.Peer ReviewedPostprint (author's final draft

Linking geometry and algebra with GeoGebra

GeoGebra is a software package and is so named because it combines geometry and algebra as equal mathematical partners in its representations. At one level, GeoGebra can be as a dynamic geometry system like other, commercially available, software. But this is only part of the story. Another window (the algebra part of GeoGebra) provides an insight into the relationship between the geometric aspects of figures and their algebraic representations. Here each equation or set of coordinates can be edited in the algebra window and the figure instantly changes. What is more, an equation (or a function) can be typed into the space at the foot of the GeoGebra interface and the corresponding geometric representation will appear in the geometry window. Perhaps utilising GeoGebra could inspire a change from regular forms of enrichment/ extension activity to things that need high level thinking, and things that pupils may find themselves wanting to follow-up outside school lessons

LNCS

Let C={C1,...,Cn} denote a collection of translates of a regular convex k-gon in the plane with the stacking order. The collection C forms a visibility clique if for everyi < j the intersection Ci and (Ci ∩ Cj)\⋃i<l<jCl =∅.elements that are stacked between them, i.e., We show that if C forms a visibility clique its size is bounded from above by O(k4) thereby improving the upper bound of 22k from the aforementioned paper. We also obtain an upper bound of 22(k/2)+2 on the size of a visibility clique for homothetes of a convex (not necessarily regular) k-gon

ZCAP Research And Development: Final Report

ZCAP is a suite of terrain database correlation tools created by IST. This document is a report on the steps taken to meet the goals of handling a larger set of database formats, accessing the quality of terrain data contained in larger databases, and investigating approaches to improve the usability of the ZCAP correlation. The report details the results of the research and suggestions for future directions in terrain database research

Archaeological 3D GIS

Archaeological 3D GIS provides archaeologists with a guide to explore and understand the unprecedented opportunities for collecting, visualising, and analysing archaeological datasets in three dimensions. With platforms allowing archaeologists to link, query, and analyse in a virtual, georeferenced space information collected by different specialists, the book highlights how it is possible to re-think aspects of theory and practice which relate to GIS. It explores which questions can be addressed in such a new environment and how they are going to impact the way we interpret the past. By using material from several international case studies such as Pompeii, Çatalhöyük, as well as prehistoric and protohistoric sites in Southern Scandinavia, this book discusses the use of the third dimension in support of archaeological practice. This book will be essential for researchers and scholars who focus on archaeology and spatial analysis, and is designed and structured to serve as a textbook for GIS and digital archaeology courses