Irrlicht Engine

Could you give a textual example of how you would tackle this?

I would do something similar to what Q3 did, precalculate a pathing grid for each level. The bots can then move using that. You don't need millimeter resolution to tell the bot to "go up that hill and open that door" - the pathing grid could be at, say 0.5m, and you'd do smoothing client-side so they don't fall inside the terrain.

@CuteAlien and Hendu, Thanks for your input! It's very helpful!

@sidu, Nice game! Looks great and I don't see any delay.