In my voxel game, I'm looking at making NPC's use A* to path-find. I've got a couple parts of this I'm having trouble figuring out/implementing. Mainly, I'm having difficulty when it gets to two different (but possibly occurring together) scenario's:

- There are a ton of NPC's trying to path-find, and
- There's a large distance to path-find to.

I'm not sure how to choose between multi-threading, using multiple frames, or exactly how to implement this. Any suggestions, paper's, books, websites, etc?

Thanks,

ST