Hello
I have followed the debates about VRML/X3D for weeks, and it's time to speak.
The aim of our project is to make botanical data available on Internet, including 3D images.
We need a compact, non proprietary, preferably XML, clean definition for complex 3D geometries.
It seems that a representation both compact and flexible should be based on mathematics. VRML's cones and cylinders are just special cases of intersections of volumes defined by equations: f(x,y,z)>=0
NURBS and Beziers patches are just special cases of surfaces defined by 3 functions R2 ---> R3 (u,v) ---> (X(u,v),Y(u,v),Z(u,v))
A solution is to use the content part of MathML. I have reviewed it: it has the desired capabilities, i.e. allows to define functions and sets, it is XML. Certainly only a subset of MathML is needed: n-dimentional geometry, n>3 is not relevant. On the other hand, some geometrical primitives could be added : - convex hulls, - recursive constructs like fractals and L-systems, - transforms, deformations, parametrization, movement
My second point is about modular schemas versus monolythic Schemas. X3D is a very "good" example of monolythic DTD. NOTHING is taken from the XML world outside X3D.
It seems that Virtual Reality involves several layers that can be used and designed independently: - volumic objects definition (see above) - colors and textures on volumic objects - behavior of volumic objects among them (contact, glued or sliding, rotating, interpenetrable, etc) - behavior of volumic objects with User Interface - a scene as composite Design pattern of volumic objects - light sources - scenarios (time-dependant aspect ) - sounds
Conclusion:
This need for a compact, non proprietary, preferably XML, clean definition for complex 3D geometries is common with other important domains: - Computer Aided Design - Architecture - simulation in mechanics, physics, and biology
CAD is a very important field that has currently no XML non-proprietary language. It seems that the proposed solution could bring an interesting synergy able to speed up developments, together with a better design. And also a common subset for CAD and Virtual Reality will bring new possibilities to exchange data. A well-designed model and XML syntax for virtual reality could also be used for cartoons and video games.
-- <person> <first_name>Jean-Marc</first_name> <name>Vanel</name> <project>Worlwide Botanical Knowledge Base - making botany available on Internet <a href="http://wwbota.free.fr/" >site</a> </project> <homePage>http://jmvanel.free.fr/</homePage> <a href="mailto:jmvanel@free.fr">mail (eventually put "wwbota" in subject to route your mail in relevant folder)</a> </person>