Looking for information on how Passive AI moves

[MercurialCaffeine]

I build NPC housing around the movement of NPCs. I try to build it in such a way that the NPCs are encouraged to walk to and from specific rooms of the housing, but I keep running into the same issue: I have no idea how they actually move. Sometimes I build gaps for them to fall into, but they just jump across the gaps, and never fall into them. I build stairs for them to walk up, but they fall off halfway up the flight. Sometimes they fall through platforms, sometimes they don't. The wiki doesn't tell me nearly enough information to be of any use, either, so I'm asking here.

I want as much information as anyone can give me on the rules and patterns of Passive AI movement. When they do and don't go through platforms/stairs, what stairs they will climb, what terrain they can descend down, all of that stuff. It's important because it directly impacts how housing should be built.

 

[Banmei]

I may be able to help you out. I build my NPC housing based entirely off of their movement (as far as reachable places go not looks).

It would help if you could provide me with what you are looking to accomplish or maybe even a picture of what you'd like.

 

[MercurialCaffeine]

I may be able to help you out. I build my NPC housing based entirely off of their movement (as far as reachable places go not looks).

It would help if you could provide me with what you are looking to accomplish or maybe even a picture of what you'd like.

I was trying to double up NPCs in apartments, each apartment having two bedrooms near each other, where the NPCs would be stationed.
The bedrooms would connect to a living room, and the living room would connect to a larger common room, where the other apartments would connect.
So the two roommates could interact with each other in their own apartment, but also go out into the larger common room, where they could interact with NPCs from other apartments.
The bedrooms within an apartment should be close enough together for the NPCs to receive happiness bonuses, but the bedrooms between apartments would be far enough apart that they're not overcrowded. I am not considering biome preferences.
At no point do I want the NPCs to be forced to go through someone else's apartment/bedroom in order to get somewhere else.
Ideally they could also travel to common rooms on other floors, but this isn't as necessary.

My first attempt looked like this.

Spoiler: Image

It worked for the bottom floor, but only when the top of the flight of stairs was made of solid block, since they'd decide to fall through partway up. It does not work for the top floor, the NPCs refuse to descend or even leave their apartment.
I intend to renovate this concept because the bedrooms are too far away from each other, and too close to bedrooms from nearby apartments. I was thinking that the bedrooms could be on top of each other to make this work.
This also leads into an issue with the stairs. If it doesn't work, it doesn't work, but if possible, I'd like a more space-efficient way to get the NPCs into the common room, because the stairs occupy a lot of room that could be used for furniture.

 

[Banmei]

You've got part of it down. The stairs to the top right won't work because they are not connected. The AI doesn't process this.

The basic concept of: Bedroom to left of living room, Bedroom to right of living room, Living room inbetween bedrooms is good. The seem to want to socialize when they are alone. They don't know what they are missing.

The rest you could rework. Do note that they only wander so far so you may want to shrink things if you really want them to come together in a common area. You can get away with having a 7 wide by 6 height room for each one. I think the bottom stairs do not work because they are too tall. Shortening the floor depth would help too. For the top just reverse the same as the bottom as they can walk down stairs.

The common area will be tricky if you have more than 4 Npcs. Instead of doing a square trying something more star like with the common area being in the middle, and the paths from the living rooms go diagonal towards it.

This is a concept and what-ifs though, so if you do try my suggestion try using dirt (it breaks quicker) and test just a section out at a time. You can always use block swap to change out to your desired blocks once you have the configuration that you want. I'm not 100% positive that this post will work.

Lastly, having that many NPCs in a close vicinity will negate their happiness bonuses so if happiness is of concern this might not be worth while.