AC3d's VRML2/97 is a very limited export. It exports Shape nodes, the geometry/material nodes you find inside a Shape node, and a Pointlight node.
So if you have a collection of objects it exports them as a long list of shapes - no hierarchy - except that they are arranged in in the same order you that is shown in the hierarchy box. So NO Transforms or Group nodes.
This can be a benefit ... but sometimes a little awkward.
The benefit is all the co-ordinate values are absolute ... no need to transform them. I am told ... this speeds up the rendering in a vrml browser as there are no calculations to do. If you want to make sure a group of objects are associated just drop a Group node around those objects ... not a big deal.
The draw back .... if you create a column .... and want to make a row of them ... using the DEF/USE becomes messy. So your vrml file is a little bigger.
Personally, I have got used to this little drawback, and tend to create knowing this. I also think that the vrml exported from AC3D ... while a very basic vrml ... it is some of the cleanest code you can work with ( I know of at least one program that buries geometry in the many transforms it creates - no names though ;-) .)
As for importing VRML2/97 lots of features are designed for animations /scripting etc ... something that was not in VRML1. Until AC3D goes beyond a geometry modeler and has animation features ... will probably be NO import of VRML2/97.
If you wish to get some vrml2/97 back into AC3D you can use a program like Accutrans 3d (
http://www.micromouse.ca/) and export in VRML1 or .obj format to get the geometry.
Just my thoughts
griff