It looks like, there is no VRML export in i3d
$ cd i3d-0.66
$ find . -name '*.h' -print | xargs grep -i vrml
$ find . -name '*.cpp' -print | xargs grep -i vrml
VRML is the ISO standard to distribute 3D data through
the web.
The coming version of VRML200x also supports nurbs.
Tools like white_dune
(http://www.csv.ica.uni-stuttgart.de/vrml/dune/)
already support the coming nurbssurface Node.