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3-D APIs Conserve Bandwidth
By Erick Von Schweber and Linda Von Schweber
October 31, 1997 5:42 PM PST
PC Week

The advanced 3-D APIs being incorporated into industry-standard Web browsers can significantly reduce network traffic compared with image-based technologies such as bit maps and digital video--for some applications, the reductions are on the order of 1,000-to-1.

The three-dimensional technologies range in complexity, requiring varying levels of input from administrators. For example, getting started with the bandwidth-conserving VRML (Virtual Reality Modeling Language) 3-D file format and Oracle Corp.'s VRML Cartridge for database connectivity is straightforward. More sophisticated approaches, using 3-D tool kits from Silicon Graphics Inc., Hewlett-Packard Co. and Sun Microsystems Inc.'s JavaSoft Division will require network administrators to collaborate as part of a team with graphics developers, engineers, specialists in distributed computing and database administrators. The results will be well worth the effort, however.

Bandwidth-conserving business graphics

Network administrators supporting graphing, charting, diagramming, online analytical processing and data mining, and similar symbolic, image-based output should take a long, hard look at the VRML 2.0 file format, which can improve performance for both Internet and intranet applications.

VRML 2.0, developed to support interactive, animated 3-D graphics on the Web, also includes support for 2-D graphics and many of the dynamic features of dynamic HTML, but in an adopted standard.

A VRML file representing a 2-D bar chart can be built from geometric primitives, such as cubes and cylinders, and takes up only 1KB of space. Even compressed, low-resolution image formats (such as partial screen, 72-dot-per-inch GIF files) take up more than 20KB each. Replacing GIF charts with VRML charts amounts to space savings on the order of 20-to-1.

If a complex 3-D chart is needed, multiple GIF files are required to view the data from all angles, easily exceeding 100KB. A VRML file, in contrast, remains 1KB, netting a 100-to-1 improvement or better.

In addition, the VRML file can be animated and interactive. Accomplishing animation with image-based technology requires either animated GIFs or digital video files, both of which get very large very fast, and neither of which is interactive.

Advanced 3-D tool kits

Corporate network administrators and software developers seeking to reduce network congestion while squeezing ever more data through their networks should also exploit the new graphics tool kits and the distributed graphics architectures these tool kits make possible.

Until just recently, client/server and n-tier architectures (and the network benefits they afford) were all but unavailable to the developer of graphics applications, except in the very largest industrial organizations.

The recently introduced APIs for networked 3-D graphics, graphics connectivity to databases and tool kits for Very Large Model CAD applications enable organizations of more moderate size to reap the benefits with far less development.

For example, in the past, manufacturers' only alternative to shipping clay models from department to department was to send high-resolution 2-D renderings of models across the network. However, 10 renderings weighing in at as much as 500MB each could mean 5GB of data going across the network.

High-order 3-D surface representations such as NURBS (Non-Uniform Rational B-Splines) can represent the same model, consuming between 5B and 10MB, an effective savings of up to 1,000-to-1 over the high-resolution bit maps, and even a 100-to-1 advantage over the efficient VRML geometrical format.

The big picture: Synergistic manufacturing

Conserving network bandwidth is a top concern for administrators, but the new APIs also help disparate departments within a company work together.

For example, a company's design team members collaborate across their network segment using CAD design tools based on the new Very Large Model CAD tool kits such as SGI's Optimizer (available free of charge and already shipping for NT and Irix, with ports to Solaris and HP-UX due by the end of the year) and HP's Direct-Model (now available from HP to ISVs for HP-UX, Windows NT and Irix, and slated for wider availability sometime next year). Microsoft has licensed DirectModel for inclusion in a future version of DirectX, with availability likely in the same time frame as NT 5.0 (due next year).

High-level NURBS surfaces for a car body can be stored in a design repository database, and other teams--such as product development, manufacturing, cost accounting and quality assurance--could easily access these NURBS models from their workstations over the corporate intranet.

An application server on the corporate intranet pulls the high-level NURBS models from the data repository and tessellates them into real-time, interactive 3-D VRML models for a variety of desktop and Web users in marketing and sales. Marketing can then make these VRML models of a proposed new car accessible from the corporate Web site for consumers to browse over the Internet, forming ad hoc focus groups.

Using Oracle's VRML Cartridge (currently in beta) for its CORBA (Common Object Request Broker Architecture)-based Web Application Server 3.0 (shipping now for Solaris and soon for Windows NT), these models can be parametized, allowing users to select colors, wheels and options from the database without retransmitting whole new models over the Internet for each configuration, saving more bandwidth and reducing latency.

Java3D, a networked 3-D graphics tool kit from JavaSoft, can serve as the platform for building even more sophisticated Java and VRML applications. Java3D is available as an early specification but is currently lacking a reference implementation.

With client software built using the same CAD tool kits as the design team's, each team gets real-time, interactive 3-D models appropriate to their tasks and computer platform. This is made possible by algorithms provided by the CAD tool kit that use techniques including model simplification to render only visible surfaces, and tessellation, which takes a compact NURBS model and decompresses it into a geometrical format and quality appropriate to a client's rendering abilities.

Such operations also can be executed on remote computers over the company intranet by wrapping Optimizer or DirectModel functions as CORBA or Distributed Component Object Model objects. This saves time and bandwidth, and elevates collaboration to a new level.

In the scenario described above, individual corporate divisions work as a unified team, with marketing feedback going immediately to designers and developers. Manufacturing and quality assurance teams can now work rapidly with the product development team, for example. The bottom line is less time to market with a product that is more likely to succeed. The organization acts as a whole rather than a loosely connected group of separate functions.

Much of this technology has been implemented in Oxygen, a digital prototyping tool available since April from Prosolvia Clarus that is based on SGI's Optimizer. In addition, Engineering Animation Inc., the co-developer with HP of DirectModel, has announced VisFly 2.0 and VisMockUp 2.0 for Windows 95 and Windows NT, a viewer and digital prototyping tool, respectively, both based on DirectModel.

And putting this technology into action is the Jet Propulsion Lab, in Pasadena, Calif., which is collaboratively developing the next-generation Mars Lander by supplementing its use of VRML with Muse Technologies Inc.'s Continuum. Continuum lets geographically separated team members simultaneously explore a design environment, have discussions and make comparisons.

Division Inc., of San Mateo, Calif., supports similar collaboration across the network with dVISE, a distributed system for product simulation. And Sense8, of Mill Valley, Calif., has announced Pangea, a networking product for creating multiuser 3-D simulation applications for intranet or Internet deployment (with client support planned for Windows 95, NT and SGI's IRIX, and server support for NT, IRIX and Sun).

Separately, Sense8 is working with Engineering Animation Inc. to extract VRML 1.0 files from a VisFly or VisMockUp model, and load them in an application built with Sense8's WorldToolKit or WorldUp products for immersive viewing.

Erick Von Schweber and Linda Von Schweber are principals of Infomaniacs, a think tank in Sedona, Ariz., specializing in technology convergence. They can be reached at or

Erick Von Schweber and Linda Von Schweber are principals of Infomaniacs, a think tank in Sedona, Ariz., specializing in technology convergence. They can be reached at or

Copyright © 1997 Ziff-Davis Publishing Company

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Updated Jan 28, 1998