Manifest 3D: A Framework to Develop 3D Graphics Applications

2004

Having discussed necessary basic technologies and information visualization techniques in Chapter 2, we need to turn our attention now to requirements for the research work to be carried out in connection with the present thesis. A number of related projects will be presented and analyzed in this context. The deficits found in existing applications will be used to define new requirements, leading, in the end, to the formulation of more detailed objectives of this thesis. The projects presented in the following have in common, that they provide a framework for applications, which map database content to visual content using three-dimensional metaphors. They are presented from a rather conceptual view without going into very much technical detail. In section 3.7 we will comment on some interesting and relevant technical achievements of the projects described. The order in which the projects are presented roughly reflects their chronology.-69-tomers. With a full compliment of robust components for rapid application development, Open Inventor has become an even more powerful graphic display system for real-time 3D visualization. Open Inventor allows developers to increase productivity by reducing time to market and optimizing their development costs and resources. Open Inventor in its current version supports a number of impressive 3D graphic features, such as: • Advanced multi-pipe capabilities (with Multi-Pipe extension) • Volume rendering (with VolumeViz extension) • Large model visualization • Ability to handle large data sets • Real-Time interaction • Server software that generates 3D images over a network Open Inventor gives the developer a choice of development language, either C++ or Java, and also provides the flexibility of running the developed application on many different platforms. This cross-platform capability makes Open Inventor a fast, flexible, and high performing API for developing interactive, object-oriented 3D applications (http://www.tgs.com/). Sample application areas for the TGS Open Inventor include Business Graphics, Cartography, Chemistry, Engineering, Virtual Reality and VRML, AEC and Simulations, Mechanical CAE and CAD, Architectural Design, Medical and Scientific Imaging, Geophysical Sciences, Scientific Data Visualization, and Animation. Figure 35 depicts an example CAD application including the visualization of the structure of an engine part. By now, Open Inventor is the de facto standard for development of cross-platform (IRIX, Solaris, HP-UX, AIX, Linux, and Windows) 3D graphics applications in C++ and Java. It is a powerful object-oriented toolkit with over 450 classes and an intuitive and easy-to-use programming interface that allows for rapid prototyping and development of graphics applications. 3 RELATED WORK-71-3.3.3 GROOP The authors of [Koved,1993] detected an increasing need to provide tools for application programmers that were easier to learn and use, yet retain flexibility for a wide range of modeling, animation, visualization and Virtual Reality applications. The challenge was to define intuitive programming interfaces for programmers who have a rudimentary understanding of 3-D geometry, yet have no prior knowledge of computer generated graphics. The GROOP system (GRaphics using Object-Oriented Programming), which was introduced by Koved and Wooten in [Koved,1993], is a toolkit for animated 3D computer graphics. The basic metaphor is derived from theater or motion pictures-a scene-composed of a stage (display), actors (3D objects), lights and a camera. For the novice, simple animated models can be quickly constructed by creating objects, adding them to a scene, and applying transformations (scale, rotate and translate) to generate animation. To simplify learning and provide consistency, an object-oriented language with inheritance is employed, yielding code reuse and permitting the construction of reusable 3D objects with behavior [Koved,1993]. 3 RELATED WORK-75-Furthermore, by allowing the programmer to describe the 3D scene using coarser-grained graphical objects, as well as by defining objects for elements such as appearances, transforms, materials, lights, etc., code is more readable, maintainable, reusable, and easier to write. Java 3D uses a higher level scene description model, the scenegraph, which allows scenes to be easily described, transformed, and reused. Java 3D also includes a view model designed for use with head-mounted displays (HMDs) and screen projectors. By insulating the programmer from much of the complex trigonometry required for such devices, Java 3D eases the transition from a screen-centric rendering model to a projected model, where rendering in stereo allows for greater realism. Java 3D additionally includes built-in support for sampling 3D input devices and rendering 3D spatial sound. Although Java 3D includes many optimizations, a skilled developer using OpenGL and native C code will probably achieve higher performance than a Java programmer using Java 3D. If absolute rendering performance is the top-priority for an application then it might be better using OpenGL or another native rendering API. One particular problem, inherent in Java, which can be noticeable in performance critical applications, is the impact of the Java garbage collector (GC). The Java runtime, the Java 3D runtime, and the application code all create objects. All these objects will eventually become garbage, and be collected by the Java Virtual Machine (JVM) GC. While the GC is running there may be an appreciable system slowdown, resulting in several rendered frames being dropped. If garbage collection occurs in the middle of a critical animation sequence, the realism of the rendered scene may be lowered for the user. FIGURE 39 The Java 3D fly through example Another limitation is that the Java client-side APIs, and especially Java 3D, can be difficult to distribute to end users. While the biggest group of end users run Windows, Sun has had limited success getting Java 2 (JRE 1.2) deployed on the Windows platform. Java 2 is required for Java 3D, although Microsoft's JVM does not support Java 2. This means that end users are required to download Sun's Java 2 implementation, install it, and then download Java 3D and install it, all # Motive Style Artist

Proceedings of Seventh Annual IEEE Visualization '96, 1996

The Visualization Toolkit (vtk) is a freely available C++ class library for 3D graphics and visualization. In this paper we describe core characteristics of the toolkit. This includes a description of object-oriented models for graphics and visualization; methods for synchronizing ...

… , 2009. ACHI'09. …, 2009

Proceedings of the seventh international …, 2002

Even though numerous Web3D technologies exist, most of them do not support a high-level, multi-disciplinary authoring process. Moreover, concepts of reuse are rarely provided. A componentbased approach is introduced with the CONTIGRA architecture to construct interactive, three-dimensional applications, either stand-alone or web-based. The approach is entirely based on declarative XML documents describing the component implementation, its interface, as well as component configuration and composition of 3D user interfaces and virtual environments. Extensible 3D (X3D) is used as the scene graph basis. However, the resulting applications can be translated to other 3D technologies, too. Another advantage of the approach is reuse both at the implementation level and the higher abstract component level. This paper introduces the overall architecture and the XML schemas used for the component documents. It finally outlines the associated authoring process and tools involved.

Technical Report CS: 2003-04, Chalmers Department …, 2003