This is one of these questions I never thought to ask before because it seemed fairly straightforward--until I really thought about it, oh ten years after using them (and struggling with their annoying little glitches). But if you have a cell that's only ever going to be inhabited by you and maybe some companions (hopefully all with follow scripting), are they really necessary in every tiny cell? I hate working with the things so much, maybe I'm just looking for any excuse to get out of doing them, but are companions really going to be more jammed into a place like a tiny bathroom and not walking into walls any less without them? Because even with a path grid, AI pathing in such tiny spaces svcks so much, you're pretty much relying on warping to get your companions out of there again.
So. Path grids. Totally useless in those situations or should I still bother?
But questions aside, let's take a moment to [censored] about path grids. Like when you stop one short of a barrier or ledge, but the NPC hits it and never stops walking. So instead of stopping at the fence or on the edge of a balcony and gazing meditatively over it, they try to walk into or off it, never getting anywhere. They just keep walking and walking and walking.
And how about when you set one neatly in the center of a wide hall with no obstacles and assign it position in the AITravel function, but the capricious engine has decided your path grid is not the absolute correct z-height relative to the floor, even though the difference can be measured in pico-whatever-units, so the AI is never going to finish that wander package. Ever. Hope you like the taste of failure, because no matter how many times you adjust it, load the game, watch the NPC do nothing, exit, load the CS and try again, they will never get there.
Oh, oh, and hey, how about when you generate a default path grid and it leaves several halfway up a wall, so the NPC would be trying to climb a bookshelf or something. Gotta love that.