You didn't do the navigation markup. How is that just suddenly there?

Because we already had one with this one, so I kind of cheated here. But I will actually do one so you guys can see.

Navigation is a volume that we put down. And in this case, it's just a giant volume. And then the system generates everything inside the volume, checks all the surfaces, and generates a valid nav mesh. Ideally, of course, each room would have a more detailed version, like what he's doing now. But for testing, it's just fine to put down a giant box.