Re: Open Inventor *as* VRML

Gavin Bell (
Fri, 9 Sep 1994 14:59:01 -0700

On Sep 9, 3:50pm, Linas Vepstas wrote:

> There have been numerous publications in the trade that have
> negative comments about the technical implementation of Inventor.
> Since I've heard even more negative things in private conversation,
> I can only conclude that you interviewed a narrow segment of the
> population.
> See: (Why can't I find my copies when I need them?)
> 1) "A Declarative Representation System for Dynamic Visualization"
> Mark Alan Tarlton, dissertation, Univeristy of Texas, 1993
> 2) Several arcticles emanating for Brown University group, e.g.
> the 1993 Course on Object Oriented Toolkits at SIGGRAPH.
> 3) "GROOP: An object-oriented tookit for animated 3D graphics"
> Larry Koved, Wayne L. Wooten, OOPSLA '93
> > [ ... ]

We don't like their systems for various reasons, too. Just healthy
criticism. The bottom line is that lots of people are using Inventor
for lots of interesting things; it has proven itself in the real world.

> I beleive that similar remarks apply regarding extensions &
> enhancements. I've even gotten Gavin Bell to admit that its
> hard to add a new primitive to the system (I apologize that
> I have to quote you, Gavin).

I'll try to restrain my response....

We designed Inventor to be extensible. Extending is inherently more
difficult than just using the existing objects that somebody else has
already designed, implemented, debugged, redesigned, reimplemented, ...

Inventor is much, much, much easier to extend than Motif. Infinitely
easier for a user to extend than GL. I'm sensitive about this because
we tried really hard to make it extensible; implementing things so they
were extensible made our jobs at least twice as hard. Of course we
didn't do a perfect job-- but see the Inventor Toolmaker for detailed
instructions on how to add new nodes, actions, manipulators, devices,
events, viewers,....

Perhaps Kevin Goldsmith can comment on the work he did for the Out Of
Box Experience, in which he extended Inventor to an incredible degree
to support interactive movies and audio and other cool stuff.

> I would be very open to basing a VRML that was a stripped-down
> of the Inventor file format. There is a lot of goodness in Inventor,
> along with a lot of junk.

I'm working on this; I should have something ready for public scrutiny
in the next couple of days.