The long-awaited Cities: Cities: Skylines 2 was released this month, but unfortunately not in the best of conditions, with PCG's Chris Livingston noting in his review that "it's a sequel with big improvements, but there are quite a few disappointments," the latter included some serious performance issues. These affected so many players that the developer, Colossal Order, went into hiding to reassure players.

Do they know what is "deep-seated"? And Cities: Cities:Skylines researchers are trying to find out what is behind the problems players are seeing. The conclusion they and others have come to is that the performance problems stem from the game trying to render the teeth of individual citizens, even when zoomed out.

The game simulates the events of typical urban life to a fine level of detail and renders the bodies of the citizens to reflect that. The player then claims that the game simulates the teeth of individual citizens down to the level of rendering, thereby degrading the overall performance of the simulation. This claim was quickly taken up and amplified.

Publisher Paradox has now sent a written response to these stories about teeth. Developer Colossal Order's statement follows, but one explanation of the terminology is that level of detail (LOD) is the reduction of detail in a model as it moves away from the camera so that the PC does not melt when the player zooms out of the city view

"Level of detail" is a term used to describe the level of detail of a model as the player zooms out of the city view.

"The Citizen lifepath feature has nothing to do with the geometry of the Citizen and does not affect the performance figures of the character. We know that further work is needed as the character currently lacks LOD which affects some of its performance. We are working to bring these into the game along with general LOD improvements across all game assets. Characters feature a lot of detail, and while seemingly unnecessary now, will be relevant to the project in the future.

The statement further links to a developer blog post on lifepath simulation and how to generate citizen characters. However... There does not seem to be any specific mention of teeth. The reddit post that started all of this may have drawn the wrong line of causality, but the above left me with more questions than answers.

So I asked the studio for clarification on the teeth. Specifically, because I am not sure why the life path side is being mentioned, or if that is the complaint in the first place. I also asked for a little more detail on the "LOD affects some of the performance" line.

Here is the Colossal Order's response:

"The original Reddit thread suggested that citizen lifepaths require details like tooth geometry. As for the overall LOD issue, yes, LOD is one of the issues we are working on that seems to be affecting game performance. Yes, characters have teeth. No, the character's teeth do not affect performance in any way that we would call significant."

In other words, the studio believes that LOD is an LOD issue that is affecting the performance of "Cities: Skylines 2," but definitely not because of the teeth. As for whether teeth are "important," all I can say is that game development rarely makes sense to outsiders, and aspects that seem counterintuitive often make perfect sense to those who know what they are doing: The Colossal Order is fairly firm on what it thinks of this case.

As for why citizens need teeth in Cities: Cities: Skylines 2, it's all in the "future relevance" section of the initial response. Citizens need different types of medical care, and as a result, oral health may be a factor in the future. Dental DLC.

In any case, Colossal Order's statement can probably be taken at face value (sorry). It is clear that there are technical problems with the shipped game, but at least they are upfront about it and what they are doing to remedy the situation: given their long-term support for Cities: Skylines, which was released in 2015, they will eventually we can expect that they will embark on a fundamental solution to the problem.