LANG: MSDL (was Re: Object Desccriptions)

Mark Waks (
Fri, 17 Jun 94 17:00:08 EDT

Chris Hand recommends that people take a look at the docs on MSDL, the
Manchester Scene Description Language. Having just read through them,
I'll concur with that -- it's worth digging into. (Brian, Mark -- I'd
strongly recommend adding a pointer to the MSDL page from the VRML one.)

Opinions, based on a quick look at the MSDL specs:

It's got most of the same strengths and weaknesses as OOGL. I like it
slightly more, for a couple of reasons, primarily that it's a shade
more readable. It's still pretty syntactically simple, so it should be
easy enough to parse. It appears (to my untrained eye) to be slightly
more complete graphically -- that is, there are features available in
MSDL that I don't remember seeing in OOGL. (Eg, "NURBS"; primitives
for cylinders and spheres.) There are also some "shortcuts" which are
nice although not critical -- for example, it has "rotate" and "shift"
commands, as well as the full-blown "transform" matrix. Like OOGL, it
has enough inheritance for us to get by, although like OOGL, it will
require some significant rewriting in the long run for all the features
we'll need to add.

Toolwise, it's not bad. It doesn't appear to have a full-scale viewing
tool like Geomview, but it's already got a parser written, and pretty
good documents on how to interface to that parser. (Which is arguably
better -- it means people can easily develop a variety of development
tools around the parser.) The language says *nothing* about where
objects come from, which just might be an advantage -- this allows us
a lot of leeway for the browser to pick things up from the right

Rights could possibly be an issue. It isn't public domain, although
they say it's generally available for academia. We should certainly
talk to the U. of Manchester about whether they would be willing to
see us start with their work. (I suspect from the tone of things
that they would say yes, but one mustn't assume.)

I'd say that MSDL is my pick of the options I've seen so far -- it's
just enough better than OOGL as a language to give it an edge
(although not a walloping one). All in all, I like UM's approach.
Next: on to check out VRIF...

-- Justin
Who is rather enjoying the excuse to
actually learn something about 3D

Random Quote du Jour:

"16. Bad toupe
28. Used SS instead of LAPD
31. In last days, chose to hide in bunker rather than ask U.S. for a
little country place in Hawaii"
-- From "Top 59 Mistakes Made by Adolf Hitler"