Re: VRML Survey now online

Paul Burchard (
Wed, 20 Jul 94 11:07:49 -0500


Could you clarify some of the survey questions? Here are the ones I
had trouble with:

> Matrix Representations
> Allow transformations to be represented as, but not be
> constrained to, 4x4 matrices. Isn't hard to implement in
> the browser, but isn't easy to human-read.

The issue was not the format, but the generality of the supported
transformations (all projective transformations vs. just rigid
motions). 4x4 matrices just happen to be a convenient general
notation for specifying arbitrary projective transformations.

> Two-tier system: object description files and scene layout files?
> A few have suggested that have two types of files, a scene
> layout file and an object file. Both could co-exist in a the
> same vrml file, too. A vote in favor of this is a vote for
> allowing VRML files to not always have to have viewing
> directives.

Since we want to be able to inline and embed objects from around the
Web into a single scene, we obviously don't want to require every
object file to be a complete scene (with lights, camera position,
etc). I'm probably misunderstanding the question.

> Engines
> Simple well-defined engines to base variables on, like
> "time" or "door opening" or linking to an event.

What exactly is an "engine"? Are you asking if the language itself
should be required to predefine interactive behaviors for specific
objects like doors? Or are you asking whether the language should be
capable of supporting references to common scripts?

> Full Scripting Languages
> Come up with or settle on a full extensible scripting language
> for use within VRML, a la LISP or Tcl or Python.

The title is plural, but the question is singular. I don't know how
to answer, because I advocate that the system should not be wedded to
a single scripting language; instead it should have the ability to
support multiple languages through a common API.

Any clarifications you can make are appreciated. In the mean time, I
will hold off submitting my response.

Paul Burchard <>
``I'm still learning how to count backwards from infinity...''