Local avoidance for RTS-type games

I’m working on an RTS type game with dynamic obstacles in a large terrain.
The game area is around 1 km squared. There should be ~50 dynamic ‘building’ objects with ~200 NPCs waking around.
I want to use local obstacle avoidance for NPCs to avoid one another and dynamic obstacles, but I’m afraid a NavMesh might take too long to calculate, given that the terrain is procedurally generated and has dynamic obstacles. I’m currently using a grid graph and it’s working perfectly but with no local avoidance.
What do you recommend?


Local avoidance can be used with a grid graph as well if you restrict it to only avoid other agents and not unwalkable nodes. This will work just fine for most cases since pathfinding does a good job avoiding the walls.

And you can use the special RVO Obstacles to create dynamic obstacles.