I’ve heard from our good buddy Nick that the IK on the jetway is a bit confusing, even with the documentation provided. I could see how that would be the case since IK in general is a pretty steep learning curve and the jetway is a pretty complex bit of IK that 3ds Max itself can’t even visualize. Sliding joints only work in Max with the HD solver, and there’s no way we could support that in the engine. You can set the sliding joint limitations with HI or Limb solvers, but they are pretty hokey with bones. And in order to reduce the draw calls on the jetways from 13 to 2, we had to skin the jetways with bones.
Fortunately, part of the SP1 update is the autoskinning of animations (to reduce draw calls, the dreaded CPU killer) and the inclusion of skinning on shader 1.1. What does this mean? It means that you can get rid of the bones on the jetway and still have it only take 2 draw calls (1 for the jetway and 1 for the ground markings). Unfortunately, if you don’t understand IK, or haven’t worked with it extensively, this may be a very difficult task. Because of this, Nick has conviced me to create a video showing how I set up the jetway using Gmax. Some time in the next couple of weeks I’m going to sit down and capture a video that goes over the jetway as well as some other basic IK techniques for rigging characters and Nick will post it somewhere that everyone can access it. I’ll keep you updated as I progress.