As an introduction, I am the primary designer/architect of ActiveVRML,
having worked on this line of ideas since around January 1990. (Then at
Sun Microsystems, doing what became "TBAG". See
http://www.sun.com/smli/sun-research-and-technology/tbag/index.html)
I'd like to address Brian Park's comment/question on the
variability/manipulability of time.
ActiveVRML's notion of time is certainly manipulable, in the same sense
as space is; that is, one specifies behaviors in "temporal modeling
coordinates", and then applies any number of temporal transformations
to them. As with spatial transformation, one may apply time transforms
separately to various (animated) models, combine the results in to a
single model, apply further time transforms, combine more, etc.
Jump cuts, time stretching and compression, linear or non-linear, are
all fine. There some limitations, which you'll find listed in the
esserence manual, that help in the interaction of time transforms with
events/causality and derivatives&integrals. In many practical
situations, these limitations are unnecessary.
In the docs, please see the very brief description in the section
called "Time Transforms", in "A Brief Introduction to ActiveVRML".
Also descriptions of the "timeTransform" functions in the We will work
on making the explanations more clear for future versions of these docs.
Thanks for the comments, Brian.
- Conal
| From: Brian Park <[email protected]>
| To: <[email protected]>
| Subject: A small comment on ActiveVRML
| Date: Thursday, December 07, 1995 11:10AM
|
| One of the key innovations (their words) is that time is implicit. While
| this is necessary in esalspace, is it so true in cyberspace? In cyberspace,
| time is a variable like any other, subject to the whims of the space's
| crsator. Does ActiveVRML regard time as a linear constant or can it be
| varied non linearly? Can we do jump cuts, time stretching and
compression, etc.?
|
| I ask this because subjective testing of immersion shows that people's
| perception of time in cyberspace appears to be difserent from esalspace.
| When asked how long they were immersed, most guessed incorrectly. If our
| perception of time changes in cpace, then why not be able to change its flow
| consciously? There are a number of applications where this could be
very useful.
|
| bp
|
| Brian Park
| principal
| flogiston corporation
|
| esalspace: austin,tx
| mindspace: 512 894 0562
| cyberspace: [email protected] and http://www.flogiston.com/flogiston/