No abstract available.

Describes Obliq-3D, a high-level, fast-turnaround system for building 3D animations. Obliq-3D consists of an interpreted language that is embedded into a 3D animation library. This library is based on a few simple, yet powerful constructs that allow programmers to describe 3D scenes and animations of such scenes. By virtue of its interpretive nature, Obliq-3D provides a fast-turnaround environment. The combination of simplicity and fast turnaround allows programmers to construct nontrivial animations quickly and easily. The paper is divided into three major parts. The first part introduces the basic concepts of Obliq-3D, using a series of graduated examples. The second part shows how the system can be used to implement cone trees. The third part develops a complete animation of Dijkstra's (1959) shortest-path algorithm.>

This paper describes Visual Obliq, a user interface development environment for constructing distributed, multi-user applications. Applications are created by designing the interface with a GUI-builder and embedding callback code in an interpreted language, in much the same way as one would build a traditional (non-distributed, single-user) application with a modern user interface development environment. The resulting application can be run from within the GUI-builder for rapid turnaround or as a stand-alone executable. The Visual Obliq runtime provides abstractions and support for issues specific to distributed computing, such as replication, sharing, communication, and session management. We believe that the abstractions provided, the simplicity of the programming model, the rapid turnaround time, and the applicability to heterogeneous environments, make Visual Obliq a viable tool for authoring distributed applications and groupware.

Describes ANIM3D, a 3D animation library targeted at visualizing combinatorial structures. In particular, we are interested in algorithm animation. Constructing a new view for an algorithm typically takes dozens of design iterations, and can be very time-consuming. Our library eases the programmer's burden by providing high-level constructs for performing animations, and by offering an interpretive environment that eliminates the need for recompilations. We also illustrate ANIM3D's expressiveness by developing a 3D animation of Dijkstra's shortest-path algorithm in just 70 lines of code.>

This paper describes a variety of 3D interactive graphics techniques for visualizing programs.The third dimension provides an extra degree of freedom for conveying information, much as color adds to black-and-white images, animation adds to static images, and sound adds to silent animations.The examples in this paper illustrate three fundamental uses of 3D: for providing additional information about objects that are intrinsically two-dimensional, for uniting multiple views, and for capturing a history of execution.The application of dynamic three-dimensional graphics to program visualization is largely unexplored.

No abstract available.

A fisheye lens is a very wide angle lens that shows places nearby in detail while also showing remote regions in successively less detail. This paper describes a system for viewing and browsing planar graphs using a software analog of a fisheye lens. We first show how to implement such a view using solely geometric transformations. We then describe a more general transformation that allows hierarchical, structured information about the graph to modify the views. Our general transformation is a fundamental extension to the previous research in fisheye views.

This paper describes a system for constructing graphical user interfaces following a two-view paradigm: one view contains a textual representation of the interface in a special-purpose, "little" language, and the other view contains a direct manipulation, interactive editor for the user interface. The user interface can be edited in either view, and the changes are reflected in the other view. The language allows dialog boxes to be expressed in a simple and natural way, and has a well-defined mapping into the interactive editor. A base set of interactors is currently available, but the system can be easily extended with more interactors. We believe this approach to building user interfaces combines the advantages of the direct manipulation, WYSIWYG approach with the advantages of the textual, descriptive approach, and does not suffer from the limitations of either approach.

Systems for animating algorithms have received considerable interest of late as effective means for understanding computer programs. Thus far, nothing has been reported in the literature concerning nature of the displays nor to what extent displays can be created automatically. This paper addresses these two issues. The first part presents a taxonomy of displays prevalent in algorithm animation systems; the second part uses the taxonomy to analyze those types of displays that can and cannot be created automatically from unmodified source code.

An instructional computing laboratory, consisting of about 60 high-performance, graphics-based personal workstations connected by a high-bandwidth, resource-sharing local area network, has recently become operational at Brown University. This hardware, coupled with an innovative courseware/software environment, is being used in the classroom in an attempt to radically improve the state of the art of computer science pedagogy. This paper describes the current state of the project. The hardware and courseware/software environments are described and their use illustrated with detailed descriptions, including sample screen images. Some comments are included on our initial reactions to our experience to date with the environment and on our future plans.

A software environment is described which provides facilities at a variety of levels for “animating” algorithms: exposing properties of programs by displaying multiple dynamic views of the program and associated data structures. The system is operational on a network of graphics-based, personal workstations and has been used successfully in several applications for teaching and research in computer science and mathematics. In this paper, we outline the conceptual framework that we have developed for animating algorithms, describe the system that we have implemented, and give several examples drawn from the host of algorithms that we have animated.