From: Darren S Hague <Darren.Hague@brunel.ac.uk>
Subject: Architectures for VR
Date: 8 Mar 91 15:30:48 GMT
Organization: Brunel University, Uxbridge, UK



Just a response to the call for people to say what research they're doing.

I've just started my PhD at Brunel University, where I am looking at
architectures for VR. I am currently working on a layered architecture:

+----------------------------------------+
| I/O Servers (Users' headsets & gloves) |
+----------------------------------------+
| Actor Processor                        |
+-------------------+--------------------+
| Object Forms      | Object Semantics   |
+-------------------+--------------------+
| World Processor                        |
+----------------------------------------+
| Environmental Laws                     |
+----------------------------------------+

The Actor Processor mediates between the user interface (for multiple users)
and the representation and viewpoint of the Actors as objects. It also
allows access to the Object Forms (ie graphics info) to render the
environment from the viewpoint of each actor.

The World Processor mediates between the Laws of the Environment (such as
gravity, Newton's Laws, etc), and the objects they apply to at the
Object layer. This must be done in real time.

Each object is represented by two interrelated notions of Form and Semantics.
An object's form is simply its graphical information (eg position, colour and
radius for a sphere), whereas the semantics holds abstract information
such as mass, velocity, relations to other objects and so forth. These notions
are seperated in the architecture such that the scene renderer needs only
to look at the graphics database, and can safely ignore the information in the
semantics database.

The architecture is very close to that of a 2nd generation knowledge-based
system operating in real time, and I will be searching literature in 
Knowledge Representation, Real-time Simulation, Real-time Techniques,
Space-time coherency in Graphics Representations and General Systems Theory.

At the moment, I have been able to find *no literature at all* on VR
from an info. systems point of view, only HCI stuff concentrating on
hardware. Any references gratefully received!

I hope this is of use to others in the VR research community, and I look
forward to hearing from you all.

Cheers for now,
Darren Hague
Darren.Hague@brunel.ac.uk