Although we've seen bicycle helmets with shells made of everything from wood to paper, they've pretty much all featured foam cores. The 3D-printed kupol is a little different, as it utilizes a unique system that is said to offer improved comfort and safety.
Invented by Montreal-based sports equipment designer Gabriel Boutin, the kupol features a proprietary three-layer setup known as the Kollide Safety System.
Beneath the helmet's outer polymer shell is the first layer, which consists of an array of rubber "Kinetic Bumpers" that are intended to absorb low-speed impacts – they're the green things, in the image below. Below these are a "3D Kore," composed of air-filled compartments that collapse to take the brunt of larger hits. Finally, below that are a layer of over 100 sucker-shaped flexible "Oktopus" pods – the grey things.
In direct contact with the wearer's head, the pods do compress straight up-and-down, in order to help absorb direct impacts. That said, they also allow the helmet to twist sideways relative to the head when off-center impacts occur, reportedly reducing the risk of rotational injury … and just what is rotational injury?
Well, when a conventional helmet hits the road (or anything else) at an angle, inertia causes it to be violently tugged to one side ... taking the rider's head with it. Because the brain "floats" within the skull, it moves a millisecond after the rest of head in the event of such a sudden rotation. This results in the shearing of nerves and blood vessels, which can in turn lead to severe brain damage or even death.
The idea with the Oktopus pods is that they will take up much of the initial angular acceleration that would otherwise going into twisting the head, thereby minimizing the chances of rotational injury. 6D's ATR-1 motocross helmet utilizes a similar technology.
Additionally, it's claimed that the pods conform to the contours of the rider's head more readily than a rigid foam core while also allowing for better air circulation, resulting in increased comfort.
If you're interested, the kupol helmet is currently the subject of a Kickstarter campaign. A pledge of CAD$199 (about US$155) will get you one, when and if they reach production. The planned retail price is CAD$399 (US$311).
There's more information in the following video.
Sources: Kickstarter, kupol