Re: Several (still) unresolved issues

Nathan J. Strange ([email protected])
Sun, 11 Jun 95 14:27:07 EST

>
> 3) CSG modelling
> Once we come to implement physical dynamics of worlds we are going to have to take account of things like mass and material composition. Conventional surface modelling simply cannot deal with this. The issue of material composition could be handled by ext> ensions to the existing material node to incorporate properties such as density, elasticity etc. but this still will not help with the actual objects themselves.
> CSG (Constructive Solid Geometry) allows us to define objects which actually have real volumes (and therefore computable masses) rather than merely surfaces. It also allows for logical intersections of objects (AND, OR, NOT etc.) and dynamic transformatio> ns (eg squashing , slicing etc.) which someone has already suggested as good and useful tools.
> I propose that we need to consider implementing CSG modellling in release 1.1, certainly before we consider dunamics.
>

I like the boolean operators add, subtract, and intersect and I think they
can be used to keep VRML files smaller than they would be otherwise and
to make objects that can be more easily manipulated... add can already
be done with existing grouping nodes... DEF BOB Seperator{ } should
group everything inside seperator under the name BOB right?.. If
we add animater, or negative materials so that we can subtract out a
sphere from a cube (Does this happen when you add a transparent sphere
to a metal cube, or does it just form a glass ball on the side of the cube?)

Now the other stuff... A cgi script could do the physical modeling..
like with current VRML it should be doable to create a pool game where
you click on the que ball and it goes off and interacts with the other balls
BUT... I don't think we want to go the CGI script way.. SUN has (or
at least used to have) a CGI script othello like game off their homepage
and it was unbeleavably slow... so I imagine playing VRML pool will be
kinda like pulling teeth.. but we could still go the CGI script way if
we had ...ahem... a detailed object naming convention... then the server
could make changes to the world without having to send out the whole
.wrl...

For cool warping and deformations how about a morph node...
give a ripe apple, and then give a squashed apple... tell
the browser to fill in the in between...
for other affects, I think we could do them with a space tensor of
some kind to warp and distort an object... but these are things for
VRML 5.0, Warp.... :)

-Nathan