>When we specify an object to be fetched in VRML, we may specify one or
>two related lists of keywords. One would be a list of keywords that an
>object *must* satisfy if it is to be considered acceptable for this
>use: "We need a six-foot, left-handed fridge". Another would be a list
>of optional keywords, in priority order; the user's Browser would be
>responsible for deciding whether to fetch the exact object from the
>scene's machine, or to use a close local approximation.
Perhaps there are three kinds of fridges:
1) The default fridge, which is used unless either the scenery designer
or the user has specified another one. This can reside on the user's
local machine, or on a scenery server, in a library of standard
2) The fridge specified by the scenery designer, which overrides the
default fridge. This can reside on the user's local machine, a scenery
server, or the scenery designer's machine.
3) A personal fridge, which overrides the fridge specified by the
scenery designer. This can reside on the user's local machine or on a
This way, a scenery designer can specify the way he wants the virtual
world to look, but users can override that specification. For example,
left-handed users can specify a left-handed fridge to override both the
default fridge and the scenery designer's suggestion. Or people who
want their fridges to iris open instead of having a swinging door can
The key here is that if the scenery designer suggests a description for
an object, the user has the option to override the designer's
If the designer wants to specify that an object be used with no
substitution (not allowing the user to override with a local object
description), he'd name it something other than the standard keyword
for "fridge." Then the user's browser wouldn't use the override.
-- Ken Jenks, NASA/JSC/SD5, Space Biomedical Research Institute
firstname.lastname@example.org (713) 483-4368
"In the high-tech world, if you're not on the net,
you're not in the know."
-- The Economist, December 26, 1992
as quoted in alt.internet.services by Carl Oppedahl