Is there a way in the Collada spec to define relationships between other elements in the Collada file?
e.g. a relationship which defines the link between geometry providing collision information and the base geometry.
If not, please could this be added to the specification; maybe mesh/geometry and/or nodes could have 'params' which we could use to define this?
There are ways to relate elements to each other. Controllers elements target geometry elements to describe skinning. Animation channels target elements to change their values. The instance element reference elements to place them in the scene and so on....
For collision data, the Physics Working Group is defning how that will work in a future release.