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. 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. 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. 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. Bandwidth-conserving business graphics
Advanced 3-D tool kits
The big picture: Synergistic manufacturing
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 thinktank@infomaniacs.com
or www.infomaniacs.com.
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 thinktank@infomaniacs.com or www.infomaniacs.com.
To
Contact the authors send mail to
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Infomaniacs home is www.infomaniacs.com
Updated Jan 28, 1998