Problems syncing geometry using livelink for autocad

I am trying to build a simple 3D model in Autocad (for simplicity's sake, assume a cube). However, objects can not be parametrized in 3D, so I am confused as to how I am supposed to access dimensions after a 3D object has been built in order to run parameter sweeps when I link it with COMSOL.

Is there a way to livelink a 2D drawing in COMSOL?

Thanks!