geometry first, MathML, CAD, etc
Jean-Marc Vanel
jmvanel at FREE.FR
Wed Mar 1 08:44:27 CET 2000
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 at free.fr">mail (eventually put "wwbota" in
subject to route your mail in relevant folder)</a>
</person>
--------------8DB30C893D479C1E7735182E
Content-Type: text/html; charset=us-ascii
Content-Transfer-Encoding: 7bit
<!doctype html public "-//w3c//dtd html 4.0 transitional//en">
<html>
Hello
<p>I have followed the debates about <a href="http://www.web3D.org">VRML/X3D</a>
for weeks, and it's time to speak.
<p>The aim of our project is to make botanical data available on Internet,
including 3D images.
<p>We need a compact, non proprietary, preferably XML, clean definition
for complex 3D geometries.
<p>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:
<br>f(x,y,z)>=0
<p>NURBS and Beziers patches are just special cases of surfaces defined
by 3 functions R2 ---> R3
<br>(u,v) ---> (X(u,v),Y(u,v),Z(u,v))
<p>A solution is to use the content part of <a href="http://www.w3.org/TR/MathML2">MathML</a>.
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 :
<br>- convex hulls,
<br>- recursive constructs like fractals and L-systems,
<br>- transforms, deformations, parametrization, movement
<br>
<p>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.
<p>It seems that Virtual Reality involves several layers that can be used
and designed independently:
<br>- volumic objects definition (see above)
<br>- colors and textures on volumic objects
<br>- behavior of volumic objects among them (contact, glued or sliding,
rotating, interpenetrable, etc)
<br>- behavior of volumic objects with User Interface
<br>- a scene as composite Design pattern of volumic objects
<br>- light sources
<br>- scenarios (time-dependant aspect )
<br>- sounds
<p>Conclusion:
<p>This need for a compact, non proprietary, preferably XML, clean definition
for complex 3D geometries is common with other important domains:
<br>- Computer Aided Design
<br>- Architecture
<br>- simulation in mechanics, physics, and biology
<p>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.
<br>A well-designed model and XML syntax for virtual reality could also
be used for cartoons and video games.
<br>
<p>--
<br><person>
<br> <first_name>Jean-Marc</first_name>
<br> <name>Vanel</name>
<br> <project>Worlwide Botanical Knowledge Base -
<br> making botany available on Internet
<br> <a href="<a href="http://wwbota.free.fr/">http://wwbota.free.fr/</a>"
>site</a>
<br> </project>
<br> <homePage><a href="http://jmvanel.free.fr/">http://jmvanel.free.fr/</a></homePage>
<br> <a href="<a href="mailto:jmvanel at free.fr">mailto:jmvanel at free.fr</a>">mail
(eventually put "wwbota" in subject to route your mail in relevant folder)</a>
<br></person>
<br>
<br> </html>
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