This command calculates the obstacles by using a plain at a height specified by one of the parameters, it calculates where the geometry intersects the plain then creates the obstacles from this.
After calling this command you must call
AI Complete Obstacles, this causes the AI system build the obstacles from the data that has been added to the system.
If this is not the case then I would hazard a guess that your walls either fall below or above this plain, which would result in them not being added to the system.
If you create a ghosted plain at the height you passed into this command you will see where it intersects the geometry.
Who is your Daddy, and what does he do?
