Over the course of days, weeks or months, robots can be seen scurrying across the landscape and, at a nearly imperceptible pace, a building slowly rises from the ground into the sky above.

It may not be as wild a vision as it seems now that a group of students led by Professors Jason Kelly Johnson and Michael Shiloh in the Architecture Advanced Options Studio at the California College of the Arts have created a 3D printing robot they've dubbed Geoweaver.

The hexapod robot travels on a set of wheels and, decked out with an extruder, rolls across large expanses to print structures beyond the scope and size constraints of most 3D printers.

It's an interesting, and perhaps even revolutionary, idea which might well lead to some stunning breakthroughs in printer design.

If you can imagine the possibilities posited by an "extruder robot" capable of creating large, complex objects without a traditional 3D printer bed architecture, then you have the gist of the idea. Now imagine a team of such robot extruders, all capable of various movements and able to build a variety of specific directions and depths, and you'd have a sort of Additive Army at your disposal, freed of the current limitations on size and depth.

Remove the necessity of  using materials which require a heated bed and the possibilities are further expanded.

According to the CCA team, they've already envisioned a version of the Geoweaver guided by GPS satellite data. It's not much of a stretch to imagine a team of robot extruders which could return to a source of material to refill their stocks before returning to deposit their loads precisely and guided by a single CAD source.

The result of some 60 days of research and prototyping, the team says in its current state, the Geoweaver "is a very difficult and delicate machine."

It works like this: a center mechanism utilizes two servos to control a pendulum-like extruder head, and that configuration lets the robot cover a basic XY plane which is curved to the surface of a sphere. One servo motor is used for the extrusion gear to force glue-sticks through a print head, and it's all controlled using Rhino 5 (with Grasshopper and Firefly plug-ins installed). A custom Arduino-to-Firefly firmware package completes the software setup.