Crowds - Arnold for Houdini

Object-level control for Packed Agent translation. Agents can be exported to a USD cache, eliminating the need for unpacking. Since these are object level parameters, you can mix USD cached agents and unpacked agents in the same scene.

There are various ways to configure the crowd cache:

• When rendering through the ROP, a temporary cache is created per frame and deleted after the render is complete.
• When exporting an .ASS archive, then you can choose between two modes of operation for the USD crowd cache.
  • Per-frame stores the agent geometry bind pose and enough timesamples for that frame's motion keys only. It is possible to evaluate this in parallel (in multiple Houdini sessions or across machines) since the frame cache data does not depend on each other (unless the crowd is simulated).
  • Multi-frame stores the agent geometry bind pose once, and the time samples are accumulated across the whole frame range. This gives the optimal usage of disk space, but the export process must happen on a single machine.

By default, the crowd cache is exported in the same directory as the .ASS archive, but you can set a specific cache directory if you prefer.

A simple crowd example scene can be found here.