[infogulch]

You're right that our vision gives us a 3D perception, but only in the same way that a surface in a 3D space may be stretched and squashed and even have discontinuities, but is still fundamentally 2-dimensional, it has no volume. That still doesn't give us volumetric vision.

If you had true 3D/volumetric vision, you would find painting over objects aesthetically pointless, because you see behind not just the paint, but also through every layer and sub-component of the object all at once.

For example, most "3D" video games would seem very strangely empty and hollow to a being that could perceive volumetric space directly, because games are implemented by manipulating (many) fundamentally 2D surfaces in 3D space. This implementation technique works to suspend our disbelief because we don't see 3D volumes, we see 3D surfaces.

I would also be very keen to know if the human brain could directly perceive a volumetric space.