How can I add a Unity navmesh as an obstacle in Simspace Weaver

Hi, I am just starting with simspace weaver, I looked at the Unity Ant Pheromones sample came with the SDK but I am not able to understand some basic things. In that the example I am not able to figure-out how the partitions and obstacles are generated. If I want to use a custom navmesh as the obstacle, how should I do that? Could anyone please guid me here.