I thought I posted this before, apparently I didn't.
It is a crowd sim driven entirely by Houdini POP networks. The run cycle was some mocap fbx I found online (model is mia from Motion Builder), but I had to edit it a little to fit in here.
Using the interact node in the POP network I made the particles avoid each other. Softlimit nodes to avoid the boxes. And a simple collusion node to slide on the surface of the grid.
Particles are divided in to five random groups each with different orders to avoid or follow another member of another group. They also have speed limits so they don't go off the grid.
I also added a proximity node that adds a nearest distance attribute to each particle which is basically the distance from the nearest particle. I am driving the colors of the particles with that, red is close, blue is far.
Now I am working on a way to transfer that color to the instanced geometry. I thought the point(../../xxx/,instancepoint(),"Cd",y) would pick up the color but it seems a little buggy. After the color modification is complete I'll add a feature that will change the speed of the run cycle to fit the actual speed of the particle, and maybe add a walk cycle in there if I can manage that too. Once the scene is complete, I'll clean up the *.hip file.
To be continued...