[yodon]

There are surprisingly few good representations for either 3d assets or 3d scenes.

Lots of people are pretty excited about the Universal Scene Description format that Pixar published and open sourced. It's great if you're a big film animation studio looking to manage huge scenes for offline rendering but it's explicitly not optimized for any of the kinds of speed/memory trade offs required for realtime rendering applications.

There are a couple efforts underway at the Khronos group that have lots of key folks from the Collada effort involved and there's a chance they'll come up with something good but this sort of schema design is such a subtle and forward-looking task that I personally am not optimistic about an open source effort being the first to get it right (you're trying to design a data format people will want to use two decades from now without getting trapped in a vicious cycle of analysis paralysis that can prevent you from being able to ship something usable today quickly, it's much like a language design problem where eventually you want to open source it but even then you need a Guido or an Anders or similar to guide the effort onto a good long term arc)