[uf]

It seems to me that humans can predict 3D spaces pretty good.

I've done alot of construction work. After some practice you can measure quite precisely what does fit where and even how long something is. Our brains seem to be able to "compute" such things despite all the difficulties of constructing a coherent image of our surroundings in the first place.

Or think of moving your huge couch through the narrow stairway of your house - we can predict how you need to turn it so it fits. Or think of truck drivers that are able to maneuver their large vehicles within cm range. Even when they can't see some of it (dead angles) and need to rely on their mental model.

Did I misunderstand your comment? Could you elaborate what I am missing?

[Sammi]

Anecdotal evidence: I used to work at a construction materials depot when I was younger. I remember how lost I was when I initially started, I couldn't recognize any of the material sizes by looking at them, while all the old timers always just knew what size they were just by glancing at them. Then only after a couple of months, suddenly I could too. Years later I'm still pretty good at guessing lengths, while people around me seem to always be way off. I can hold out my hands and make a foot, three feet, 1 cm, 0,5 cm 10 cm between them pretty reliably, while other people seem to be way off.

[dfox]

You can learn to estimate various geometrical quantities with surprising accuracy, but it always depends on context (scale of the geometry, distance to it and angle from which you view it).

One interesting thing that I recently noticed is that essentially everybody is going to grossly overestimate the angle of slope of road and at least while driving many people perceive curves of less than ~30° as essentially straight road.

[snovv_crash]

I'm talking about the optical illusions such as seeing a small person next to a car makes the car look bigger. Anything based on ML instead of geometry, or even using ML as a strong prior, will be susceptible to this kind of problem.