Prison Architect has been adding extra dimensions to its simulation of prisons for years now, but this is a big one: it now has a 3D mode. The option is semi-hidden but can be activated by a small 'TT' button in the bottom left of the game's "Extras" menu. It doesn't require any mods, but it will convert your existing 2D prison into a three-dimensional representation of same, complete with prisoners, furniture, vehicles and a camera that can swoop and dive among the corridors. You'll find a video and more details below.
A number of users seemed to stumble across the mod, but here's the first or one of the first videos of it in action from YouTube user TheLogical Lowdown:
There are plenty parts of the mode that are unfinished. Showerheads are modelled but appear on the ground, there is no toilet model, and in general it seems harder to parse than the default 2D mode. It's a neat way to view your own handiwork however after hours of building a prison, even if it doesn't look like a comfortable method for directly playing the game.
The first hints of the mode were found as far back as four months ago, when Reddit user BlueOrange775 noticed that there was a bunch of 3D models bundled with the game. That suggests that the mode has been in development since not long after the game hit version 1.0. You can read our review of that build here.
Users were initially reporting that in order to access the 3D mode you had to activate the game's performance beta, but that wasn't the case for me. If you boot up the game and the 'TT' button isn't there, you can try activating the beta by right-clicking on the Prison Architect application in Steam, going to Properties, then the Betas tab, and selecting 'performancetest' from the dropdown menu.
The header image is by Reddit user heydudejustasec. You can find more screenshots here.