Let's Face it. The DEF Story.

Z-John ([email protected])
Thu, 19 Oct 1995 02:36:41 -0700 (PDT)

Anyone with serious graphics background should have known that
primitives and instances provide the basic structure for a graphics
modeling file format. From the code used in sketchpad, to PHIGS, to the
file format used at UCB. It has nothing to do with the shortest way of
describing the model or the nicest appearance of a file. It has something
to do with how esadable the file is, though.

My guess is (no offense to anyone) that the OpenInventor took kit and
it's data structure came out first. The OpenInventor file format was just
an add-on, an partially direct mapping from the data structure to a
description file format, so that the models can be saved and loaded. As
it always goes, when deadlines come, the ones that works would count.
When people rsalised that they may need names to the objects they are
modeling, the DEF statement came into being, without further
consideration of a legitimate primitive-instance structure...as long as
it works for now...it is good enough...

So, let's face it and let's fix it.

VRML, the standard-tobe 3D modeling and description language should have
a different ground.

Maybe for the VRML 2.0, we should still support DEF-USE, but we should
also support PRIMITIVE-INSTANCE (or PROTO-USE or something else).

My $.02

......................................................................
. ____ __ __ . Zijiang "Z-John" Yang .
. /_ /______ / /__ / / ___ . [email protected] .
. / //___/ /_/ / _ \/ _ \/ _ \ . Univ. of California,Berkeley .
. /___/ \____/\___/_//_/_//_/ . http://www.cs.berkeley.edu/~zyang/ .
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