Preventing a NavMesh to walk on paths that are too narrow

Questions & Answers
1

Hi,

I was playing around with the Unity’s navigation system as I am about to write a new AI, and this is what I’ve noticed: the NavMesh agent is wider than it’s path, and yet it walks on it. I have some places in the game which are meant to be inaccessible to some AI (for example, if I had an oversized monkey and a midget cow in the game, I’d only want the midget cow to walk through).

Excuse my terrible job at making a screenshot, but basically, this is my problem (the green circle is the NavMeshAgent and the blue path is the navigation mesh):

[19654-screen+shot+2013-12-23+at+02.26.28+am+(2).jpg|19654]

I hope I have explained the question well. Is there a built-in way of checking if the path is too narrow, so that I could stop it from passing on?

Thanks in advance!

EDIT: After posting the question I have noticed that it is not clearly visible in the screenshot; the AI is coming from the bottom to the top, viewing from the screenshot perspective perspective (basically, after it walked across the narrow area).

2

If you have Pro, you could use Navmesh Layers – for example, one for big agents and another for small agents that can slip through thinner areas.

If you don’t have Pro, perhaps you could use a NavMesh Obstacle to close off the pinch point for big agents, or monitor for when an agent get stuck in a pinch point and steer around it.