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In a problem solving environment for geometric computing, a graphical user interface, or GUI, for visualization has become an essential component for geometric software development. In this paper we describe a visualization system, called GeoJAVA, which consists of a GUI and a geometric visualization library that enables the user or algorithm designer to (1) execute and visualize an existing algorithm in the library or (2) develop new code over the Internet. The library consists of geometric code written in C/C++. The GUI is written using the Java programming language. Taking advantage of the socket classes and system-independent application programming interfaces (API's) provided with the Java language, GeoJAVA offers a platform independent environment for distributed geometric computing that combines Java and C/C++. Users may remotely join a "channel" or discussion group in a location transparent manner to do collaborative research. The visualization of an algorithm, a C/C++ program located locally or remotely and controlled by a "floor manager," can be viewed by all the members in the channel through a visualization sheet called GeoJAVASheet. A chat box is also provided to enable dialogue among the members. Furthermore, this system not only allows visualization of pre-compiled geometric code, but also serves as a web-based programming environment where the user may submit a geometric code, compile it with the libraries provided by the system, and visualize it directly over the web sharing it with other users immediately. [ABSTRACT FROM AUTHOR]

A trip through a virtual world is a powerful metaphor and a natural way of interacting with a geographic information system (GIS). Virtual reality (VR) systems provide visual realism and real-time navigation and interaction for data in core, but fail to cope with very large amounts of data, and to provide the general functionality of information systems. We describe a prototype system that overcomes these problems by coupling two platforms: A client that runs the VR component interacts via a (local or wide area) network with a server that runs an object oriented database containing geographic data. For the purpose of accessing data efficiently, we describe how to integrate a geometric index into the database, and how to perform the operations that are requested in a real-time trip through the virtual world. [ABSTRACT FROM AUTHOR]

In this paper we describe a system, BOOLE, that generates the boundary representations (B-reps) of solids given as a CSG expression in the form of trimmed Bézier patches. The system makes use of techniques from computational geometry, numerical linear algebra and symbolic computation to generate the B-reps. Given two solids, the system first computes the intersection curve between the two solids using our surface intersection algorithm. Using the topological information of each solid, it computes various components within each solid generated by the intersection curve and their connectivity. The component classification step is performed by ray-shooting. Depending on the Boolean operation performed, appropriate components are put together to obtain the final solid. We also present techniques to parallelize this system on shared memory multiprocessor machines. The system has been successfully used to generate B-reps for a number of large industrial models including parts of a notional submarine storage and handling room (courtesy — Electric Boat Inc.) and Bradley fighting vehicle (courtesy — Army Research Labs). Each of these models is composed of over 8000 Boolean operations and is represented using over 50,000 trimmed Béezier patches. Our exact representation of the intersection curve and use of stable numerical algorithms facilitate an accurate boundary evaluation at every Boolean set operation and generation of topologically consistent solids. [ABSTRACT FROM AUTHOR]

The goal of this paper is to prove the applicability of algorithm engineering and software design concepts to geometric computing through a vertical case study on the implementation of planar point location algorithms. The work is presented within the framework of the GEOMLIB project, aimed at developing an easy to use, reliable, and flexible library of robust and efficient geometric algorithms. We present the criteria that have inspired the preliminary design of GEOMLIB and discuss the guidelines that we have followed in the initial implementation. [ABSTRACT FROM AUTHOR]