User blog:Mathmagician/Patch 1.1 - Testing NPC Housing

Motivation
A number of people have been experiencing issues with NPC Housing since Patch 1.1 came out. In particular, it has been noted that the "This housing is not suitable" message can appear in cases where players have met all of the usual housing requirements from the previous patch. This has spurred me to perform some testing to try to determine exactly how the NPC Housing requirements have changed. I have not yet reached a 100% definitive conclusion, but I have come across some very interesting results which I wish to document here. Once enough testing has been performed, I hope that my efforts can be used to bring the Housing page up to date for Patch 1.1. I will also try to see if Patch 1.1.1 changes anything as well.

Terminology
Throughout this blog post, I shall use the word "suitable" when referring to a house that, when queried, returns the "This housing is suitable" message. I shall use the phrase "NPC-valid" to refer to a house that has a visible NPC flag within it after an NPC has been assigned to that house. Note that these two concepts are related, yet distinct.

1) The Funhouse


After an hour of messing around, I was able to construct a very odd house which is both "suitable" and "NPC-valid," as proven by the flag in the picture and the messages in the bottom left corner. Please take a close look at the picture above and observe the following:
 * This house uses a Bed for its comfort item, a Work Bench for its flat surface, and a Torch to meet its lighting requirement.
 * This house does not possess a single Door. In previous patches, NPC houses always required a door.
 * This house has a ton of Wood Platforms as part of its floor and roof. You can do that!?
 * This house uses Active Stone Blocks on the left portion of its wall.
 * This house uses Ebonstone Blocks as its right wall, which is rather interesting.
 * This house has 1 solid block in its floor. This is apparently very important, as I shall attempt to demonstrate.
 * There are a series of measuring blocks outside the left wall and below the floor, so that the size of the house can be measured and my test steps can be reproduced.

2) Just Checking...


Inactive Stone Blocks cannot be used as walls. This means that they cannot replace the function of Doors. Well that's good to know I guess.

3) What's So Important About That One Block?


The only difference between this picture and the first one is that I have replaced the solid block on the floor with a wood platform. It turns out that this house is still "suitable," but it is not NPC-valid! When I clicked on the dryad's portrait and tried to assign her to the house, her flag absolutely refused to appear in the house and she would not move in at all. I can't explicitly demonstrate that in the photo, but that's what happened. I challenge anyone who doesn't believe me to reproduce my house and test it for themselves.

Conclusion: Apparently the floor needs to have at least one solid block.

4) Ummm... What?


The only difference between this picture and the first one is that I have moved the work bench one square to the left. Lo-and-behold, the house is still "suitable," but it is not "NPC-valid." I tried to assign various NPCs to the house, but it didn't work and the flag didn't appear, despite the fact that the solid block is still there.

Question: Why is the house not "NPC-valid" when the only thing I did was move the work bench one square over?

5) I Think I Get It


Hmmmm, some NPCs teleported to my house while I was away. Now then, to produce this picture, I started with my original house in the first picture, and just moved the work bench over to the right side to get it out of the way, and then I placed the bed adjacent to the solid block. Bingo! I am able to set my spawn point, the house is "suitable," and it's also "NPC-valid," as you can clearly see by the flag on the screen and the messages in the bottom left corner.

Conclusion: NPCs require at least one solid block to stand on, and this solid block must be adjacent to either a comfort object or a flat surface within the house. The reason for this is because NPCs have an AI which tells them to stand still next to one of these objects at nighttime.

6) Make Room For My Hair!


In this picture, I have placed a single stone block above where the NPC would stand at night. Apparently that won't fly, because this is another case where the house is "suitable" but not "NPC-valid."

Conclusion: The NPC requires 4 blocks of vertical space in order to stand still at night.

7) Where's The Entrance?


Before now, there has only been one entrance to the house: by dropping down through the wood platforms that form the roof. I have now replaced those wood platforms with solid blocks, so that there is no longer any entrance or exit to the house. Apparently that's not a problem, as this picture demonstrates.

Conclusion: Houses in Patch 1.1 don't even need an entrance or exit.

Thanks For Reading =)
I hope that this blog entry was informative. I challenge anyone who is interested or who doesn't believe my claims to reproduce my test steps. I have also done this in a second world with another character, so I am confident that my data can be reproduced and that my conclusions are sound. I will hopefully be updating the Housing page soon, though there are still a few more things I want to check first. Well, that's all I have to say for now, so, have fun fellow Terrarians!