I came on this project towards the end to final the bird sequence.
There was already some bird R&D in place but it was all based on noises and pop forces. There was no behaviours implemented and they pretty much went around in circles based on a path defined by a spline.

I adapted my vex based flocking setup to create an ever shrinking vortex of birds.Once all the flocking behaviours and obstacle avoidance was implemented the resulting simulations were very bird like and we chose not to do any hero animations of the birds.

For the cocoon I built a state machine in vex with state transitions and loopable clips to generate the flock setting into the coccon shape. It took a bit of quaternion magic to smoothly transition in and out of states without horrific spinning in the agents.

To render the birds I adapted the feather system to generate low res proxies with some baked in feather animation to add life to the cards. All of this was rendered in Arnold as Baked in ass files.