Multi-function spine

[Pancho]

I'm running into a problem here. Probably I have one option left, but I'd like to understand what's happening and why it doesn't work.

For a fish rig I have successfully set up a bone chain (spine) which is path constrained to a curve with a constant length. This curve is curve deformed by by another curve with clusters (point) center constrained to several nulls. Moving around these nulls gives me the position for the bone chain I want. Everything works fine.

But to automate the tail movement I need to bring in another spine which is oscillating. So the bone chain is constrained to its "bone" curve. The "bone curve" is constrained to the oscillating curve. The oscillating curve's nulls are constrained to the main deformer curve by an ICE compound. The ICE compound which is part of the main ICE tree on the one and only point cloud is although responsible for the oscillation of these nulls. Theoretically everything should work fine. My main curve deforms the oscillating curve, which is also swing around as expected, which deforms my bone curve. This works as expected. Fine!

But the bones don't follow there bone curve anymore!? I didn't changed the relationship of the bones to the chain in any way. I'd say it's because the deformations before bringing in the ICE oscillation where done traditionally, while the oscillation is done via ICE. Probably these deformations take place at different computation times, so the bones don't get the proper deformation and stay in place, not knowing what to do.

So I replaced the pathCons by an ICE tree on each bone doing the same thing. But now everything goes screwy. Even if the bones shouldn't have to do anything with the curve deformation, the curves get screwed up, collapsing more or less in space till you can't see or find them anymore.

No idea how I could solve this.

Can somebody please explain why the pathCons doesn't work anymore or give me another solution for this rig? My only idea is to replace the bone chain with nulls constrained to the curve. But this needs more computation time as the length of the curve might need to get re-evaluated all the time. Bones won't change their length, so the spine will always have the same length.

HEEELP!

Cheers
Pancho