Problems with navmesh bounds

I have a basic AI system set up in a test scene which more or less works however I am failing to fully ‘get’ the various settings in RecastNavMesh.

Below is a screen grab of my scene… AI character with obstacles and basic follow logic (follow first person camera).


First problem… I have the agent radius set to 36. Agent height 144. If I change any of these values up or down my AI doesn’t run… its as if it cant see / process the navmesh.
On a related point - why does the green navmesh display sit there in the center like that? Navmesh bounding volume is the same size as the ‘ground’ static mesh by the way. When I set the agent radius to 1 I get a more or less perfect snap to the ground geometry, but as mentioned my AI no longer runs.

Second problem… no matter what I seem to do I cant force the character to stay in the ground mesh bounds, he always follows me about a character width off the mesh, to the point where his capsule is still just in contact with the mesh bounds but no further. Why is this happening? Whats the best way to limit his movement to the bounding box of the mesh / the green area of the navmesh?

I did read through the docs and watch a few tutorials but none of them cleared this up for me. Oh - if it helps the scene is scaled via a top ‘root’ node. Maybe thats having an effect?

Thanks for any help…