If you want to see the perfect building, don’t look to the nearest skyscraper. Look to the nearest tree.

I was skeptical, too, until Steven Keating, of MIT’s Mediated Matter Group, convinced me with a rapid-fire list of facts. A tree builds itself on site. Its materials don’t come from a factory, but mostly from the air. Its structure–from the branches to the leaves–respond to its unique need for light in the context of its particular plot in the forest. And its trunk is a testament to the efficient use of materials. It usually tapers as it reaches the sky. And while the naked eye can’t tell, its core is less dense than its outer rings, because the core isn’t necessary for support.

Keating’s Digital Construction Platform (DCP) looks nothing like a tree. It’s a four-ton solar powered robot arm on tank tracks. And yet, it’s a working proof-of-concept that a machine can build a lot like a tree does, sourcing local energy and adapting to local conditions to construct a building out of local materials–anything ranging from dirt, to ice, to moon dust.

Put more simply, DCP is like a Wall-E that builds things, rather than cleaning up trash.

Though the project has been in the works since 2011, the DCP team recently unveiled a massive update to their robotic platform. It’s one part practical construction bot, one part heady architecture project.

Most existing building-scale 3D printers look a lot like big conventional printers. They involve huge gantry cranes that tower over structures, extruding one layer of cement at a time like they’re piping icing on a giant cake. For all sorts of reasons, these systems lack scalability. They’re unwieldy, the equipment itself is foreign to construction crews, the material can often only be laid from one angle (making it almost useless for arches), and the cement is often very different than what would be used on most job sites. That’s all in addition to perhaps the biggest deal breaker of them all. Layering concrete, rather than pouring it, results in weaker, less predictable structures. In short, 3D-printed concrete tends to be less strong.

DCP is different. For one, it’s based upon an Altec aerial-lift system–that’s the same sort of bucket truck you might see suspending a worker at a construction site–so it’s contractor-friendly. However, the bucket has been swapped out for a major upgrade: A Kuka robot arm typically used on assembly lines, which has been loaded with extra sensors to measure all kinds of site metrics, from topography to radiation. The tip of the arm is fit with a nozzle that can mix and spray mud, foam, or concrete–basically any viscous building material you could imagine. That nozzle can also be equipped with a grinder or welder, as needed.