I hope NBC does follow up stories on it.

Long expanses with no support below.

Can the printer print around a temporary scaffolding? With brickwork, you make a plywood jig for the arch, lay the bricks on that, and remove the jig after the mortar hardens. In the pictured castle, he got around this by making really narrow windows and pointy arches.

so it would be a matter of the stiffness of the mix, and going 1/4 inch at a time. I imagine anything horizontal wouldn't work so well without supports, but those could be added manually during the process. Definitely possible, though it would make for a less automated construction.

Amazing - new jobs created, other jobs gone - the march of progress.

The layer of concrete it lays is 1/5" x 3/4". If the walls are 6 inches thick, that's 40 passes for one inch wall height.

I find it hard to imagine the intensity of the concentration required for keeping focus on all those tiny building pieces -- making each one fit in a specific place. I am impressed on all counts. Love the gradations of color.

I imagine that it would be not difficult to print right around reinforcing steel. One could easily do post-tensioned cables that are tightened after the concrete cures, as well as just printing around rebar.

Is it several inches tall or feet, I'm wondering.
In-consistent shadows in this picture?
Photo-shopped onto a real backdrop?
Big enough for a person to walk around in?
Or a cat?

(he drifts off into an image of our future, and the possibilities.....)

btw, there are some very fast setting concrete mixes. So subsequent passes would lay new, in liquid state, onto already set 'last pass' layers.

It would be interesting to see the printer so I wandered off and found these:

---> the concrete printer: