Converting IBM Visualization Data Explorer Objects Into The
Virtual Reality Modeling Language

Version 1.2

Introduction | Goals | Design | Results | Software | Acknowledgements

Introduction

IBM Visualization Data Explorer (DX) is a data flow block diagram programming language designed for producing high quality images based on 3-D data.

The Virtual Reality Modeling Language (VRML) is intended to be a language for describing multi-participant interactive simulations -- virtual worlds networked via the global Internet and hyperlinked with the World Wide Web.

Just as HTML is a method of describing 2-dimensional text and images, VRML is method of describing 3-dimensional objects.

Goals

The goal of this project was to create a module which would allow the user to export a 3-dimensional object created within DX in such a way that the object was faithfully represented in VRML.

Design

DX objects and VRML scene descriptions are very similar. For example, the concept of a group of DX objects is the perfect analogue to the VRML group structure. As another example, the VRML separator is well represents in DX by the Xform object in that an Xform applies a transformation to an object, and the transformation does not affect its predecessor objects because it is separated from the rest of the hierarchy. In addition, both DX and VRML describe objects in terms of poly gons created by connecting data points. These similarities in structure facilitate the conversion of DX objects to VRML descriptions.

Dx2vrml is written in C, and the flow of the program is very simple:

Results

Dx2vrml v1.2 creates faithful VRML representations of most DX objects, excluding screen objects and some some types of lighting. For more information and a version history, please refer to the release notes in the distribution.

Here are two screen shots comparing an object in a DX image window, and the same object in the VRML viewer Webview.

I have also made available a sample coversion from the "Imide_potential.net" network provided with the DX distribution (usually in /usr/lpp/dx/samples/programs/).

Here is the GIF image and here is the VRML file.

Getting the Software

The software is available in two formats: You may have to modify the Makefile to support your particular workstation and DX installation. Such modifications should be very straightforward; consult the DX Programmer's Manual for more information.

Acknowledgements

Many thanks to Professor Bruce Land for sponsoring the development of Dx2vrml, and to the Cornell Theory Center for supplying the hardware to develop it on. The Theory Center also provided funding to sponsor the upgrade of Dx2vrml from version 1.0 to versions 1.1 through 1.2

My sincere gratitude goes out to Marvin Landis, a technology hero in the Visualization Support Group at the University of Arizona's Center for Computing and Information Technology. Marvin's comments on version 1.0 were the reason behind the development of version 1.1; his extensive help and our discussions proved proved invaluable during the development of the new release.

Thanks to Jonathan Alferness for finding the bug which was corrected in version 1.2.

I would also like to thank Dan Dwyer of the Cornell Theory Center Online Information Group for supporting my endeavors in various ways, and Viz Group researchers Richard Gillilan, Chris Pelkie, and Wayne Lytle for helping me out in many different ways during the course of the development.

Special thanks to Wayne Lytle for not beating me up after borrowing his copy of Graphics Gems, Volume 2 so many times.

Dx2vrml is ©1995-1996 Christopher Kline <ckline@acm.org>