You kind of have the right idea, but you're missing a few tiny bits. [ame="http://www.youtube.com/watch?v=xf71AlH-9TA"]rigging tutorial part 3: auto clavicle & switch FK IK - YouTube[/ame] He covers a good auto-clav method at 2:30-5min, but it might be good to see it from the beginning to make sure the rig is set up the…
You're doing this in 3ds max? In Maya, I find the best way is to use a cone/pose reader to get the position of the shoulder and use the dot product of the reader with set drive keys to control the rotation of the clavicle. I would assume it wouldn't be too hard to make a cone reader in Max. Here's a helpful tread:…