Re: VRML usage/DIS

Michael Sweet ([email protected])
Wed, 26 Apr 1995 21:10:34 -0400


On Apr 23, 5:48pm, Don Brutzman wrote:
> Subject: Re: VRML usage/DIS
> Michael Sweet writes:
> > [entity definitions as numbers, etc...]
> > There may be some Good Things we can inherit from DIS, such as the dead-
> > reckoning facilities, but the fundamental design of DIS is flawed in a
> > non-coordinated environment (which isn't what DIS was designed for).
>
> Although I can see where Mike might get these impressions, they are
> not completely accurate. You can define a large number of different
> entity types which are standardized. The fundamental design of DIS is
> not flawed when it comes to entities describing their own behavior in
> an efficient, network-friendly(i.e. scalable) way. Currently you can have

My comments we're aimed at the entity behavior, but rather towards the actual
imagery used for the entity. DIS is oriented towards military applications,
and the entity types (I'm talking images here) reflect that.

> 300-400 simultaneous entities moving & reporting simultaneously, which is far
> more than other wide-area-network-distributed systems have been able to
> accomplish (they usually top out around twenty). Although progress
> continues, the true bottlenecks are just now beginning to be understood.
>
> ...

There's no question that DIS scales well - my comments above support that.
Just keep in mind that while behavior modeling of entities is great in DIS,
there is presently no accepted standard for environment/entity image
databases (scene graphs, whatever you choose to call a 3-D modelled
environment). *That* is the biggest flaw in DIS.

There are other problems that make using DIS directly unfeasible, such as the
'exercise ID' and 'application ID' fields used to separate simulations on a
single network. I *do* think that DIS concepts can be applied to VRML 2.0.

-- 
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Mike Sweet 2D & 3D Software for Easy Software Products (301) 994-0377 Silicon Graphics, Inc. 20778 Wolftrap Street [email protected] Workstations Lexington Park, MD 20653 http://www.easysw.com ______________________________________________________________________________