Re: PRIMITIVES

Bernie Roehl ([email protected])
Sun, 4 Jun 1995 08:41:43 -0400


According to Omar Eljumaily:
> On Fri, 2 Jun 1995, Jeff Sonstein wrote:
> > IMHO: the torus is a very basic shape, and consideration should be given to
> > incl it in the next spec as one of the "basic" primitives...
> Interesting. I don't agree with the usefulness for authoring.

More useful than a torus would be a "revolve" node that takes a profile
and revolves it around the Y axis. That can be used to produce a wide
range of shapes, of which the torus is just one. Tapered cylinders
(or truncated cones) are straightforward; also shapes like wine bottles,
light bulbs, Ming vases, lampshades, drinking glasses, rocket ships,
umbrellas, etc etc...

If I had to add just one primitive, revolution would be it. The
bandwidth savings, espcially for curved objects, would be substantial.
The other advantage is that the browser could tesselate the object at
whatever "resolution" it chooses, or even do it at several resolutions
and choose one at render time (similar to how LOD works).

It's worth noting that the Sphere, Cylinder and Cone nodes can all be
expressed as revolutions.

-- 
   Bernie Roehl
   University of Waterloo Dept of Electrical and Computer Engineering
   Mail: [email protected]    Voice:  (519) 888-4567 x 2607 [work]
   URL: http://sunee.uwaterloo.ca/~broehl