Hmm, I'm not entirely sure what you need to do, anyway here's what a body and geom does...
An ODE body is affected by forces and mass, like gravity etc.
An ODE geom is used for collision detection.
If you create a body without a geom it will be affected by forces like gravity, but will not collide with any other objects.
If you create a geom without a body it will be static (not affected by forces etc), but it will still collide with other geoms.
An ODE body is affected by forces and mass, like gravity etc.
An ODE geom is used for collision detection.
If you create a body without a geom it will be affected by forces like gravity, but will not collide with any other objects.
If you create a geom without a body it will be static (not affected by forces etc), but it will still collide with other geoms.