How do I create "solid" barriers with tilemap?

Hi,

I've a basic game already built and have started trying to implement the use of tilemaps for faster/better/easier level design.

I was previously using sprites marked as solid for barriers and am trying to switch over to tilemaps but I can't seem to figure out how to build walls/barriers/etc. using tiles from the tilemap though.

Would appreciate any help.

P.S. Another side question, how do I make the AI "obey" the same rules as the player? They seem to ignore objects set as solid and while my current implementation of adding them as obstacles it it's pathfinder does work, the AI does sometimes clip through corners while trying to maneuver around stuff.

Ah. What a glaring solution that was...the "passable" tiles had collision boxes on them too! I split the different "materials" into separate layers of tilemaps and added the collision boxes on the "materials" that were impassable.