Pixar Crowds Chat #2

These are my notes from a chat I had with Paul Kanyuk, Arik Ehle, and Dave Ryu from Pixar about practical issues in crowd simulation for animation production...

There are two primary software packages used at Pixar for crowd sim:

1. Wilma - FSM based environment used for switching between animation cycles (non-locomoting) with .xls output
2. Massive - fuzzy-logic based environment used for blending between animation cycles (locomoting)

Massive has a few additional features not mentioned in the last chat with JD:

• lanes - these are splines with color values that control flow of "traffic"
• vision - each agent has some sort of computer vision

Problem: retargeting (animation cycles/deformers/simulation) to different timings, body sizes, etc.

• for animation retargeting they usually just end up making cycles at various speeds and then blending between them to avoid problems with IK and rate changes (i.e. the physicality of the animation is ruined)
• original anim cycle is king!  The animators put a lot of work into getting a cycle to look expressive/convincing - don't ruin it during crowd sim

Directability Problems:

• Meet very specific end poses given the start poses
• How do we get characters to look alive at all LOD?  (can we have authoring access to anim cycles w/in the crowd modeling environment?)
• Close-up crowd shots need better choreographic control (especially w.r.t. the camera shot)
• Character jitter from indecision
• Very particular actions at precise locations (i.e. high-speed precise turns w/out collisions at the edge of a cliff)
• Large, swarm-style crowds are easy in Massive.  The close-up shots with more constraints are hard.
• Getting agents to start transition animations at the right time (based on desired final position + animation)
• Dressing eye-positions to the camera

M.O. = Sim with too many characters so we can kill the bad ones off.  Also, shots are usually pretty quick so some intersection is okay (perceptually).