30 April 2020
When was the last time you had your head measured?
I don’t just mean wrapping a tape-measure around your temples, I’m talking about getting every contour, lump, bump and crevice of your dome mapped digitally. You’ve probably never done that - and why would you? Unless, that is, you had as good a reason as we do.
You may think you’ve got a “normal” head, but if you were to get it scanned in that level of detail, I promise you would be surprised to find out just how unique it is. I’ve processed over 5000 head scans and have seen all types. Here is just a handful of them; notice how shape varies as much as, if not more than, size:
3D printing and 3D scanning go hand in hand when making a HEXR:
- 3D printing is the only way to create the honeycomb and intricate cavities for removable padding, shells, straps and more.
- 3D printing doesn’t require fixed designs due to the lack of moulds, therefore each print can vary.
- 3D scanning is the only way to truly capture the variable surface that the inside of the helmet needs to conform to.
Now, I can hear you ask: what if I have loads of hair, or no hair, or wear a cap? This is a frequently asked question and yes, these things do make a difference. However, we care more about the holistic shape of your head than we do its subatomic dimensions, which can change with the alignment of the moon and the sun. HEXR is made with an offset accounting for padding, hair, and even the change in size your head undergoes with temperature fluctuations.
How does the scanning work?
It’s hard to catch a ball when you’ve got only one eye open, right? The reason for this, of course, is because it limits your depth perception. And while our brain uses a lot of clever tricks to figure out how near or far away something is, that parallax depth perception plays a central role in the computer wizardry we use to scan your head.
On the back of every HEXR scanner is a pair of eyes, exactly 80 mm apart (can you see where this is going?) Between them is a light emitter, a diode behind a diffraction grate that shines a uniform grid of hundreds of little infrared dots onto the scanning subject. Both cameras see the world in ever so slightly different ways due to their separation. This difference is very apparent with the infrared dots acting as little markers. Lots of quick calculations allow the software to figure out how far away each dot is, and so it can build up a planar view of the object onto which they’re shining.
Moving the scanner around allows the accelerometers to get in on the action; multiple planes are captured every second, from a number of different directions. The precise location data inferred from the accelerometers allows each plane to be superimposed onto one another, reinforcing the accuracy of the 3D model and of course capturing the head from all angles, not just front-on.
Generating the HEXR core
Now we’ve got an accurate model of your head, how is that used to create the HEXR core? First, we need to analyse the model. There are three key metrics that are considered when generating the custom structure:
- The size of your head. This may seem obvious, but the general size is where we start due to the variety across different heads. Subsequent calculations will vary massively depending on whether the head scanned is teeny-tiny or André the Giant’s.
- The mass of your head. Thankfully, we do not need to chop it off, weigh it, then duct-tape it back as part of the fitting process! Head densities are constant enough that we can infer them from the volume measurement provided in the scan.
- Localised curvatures. This is the biggie, and something most people don’t know about HEXR. Not only does the inside surface of the helmet mirror your head for maximum comfort, but the honeycomb structure radiates out perpendicular to your head at every. Single. Point. This means that the mechanical properties (hugely important when absorbing energy in an impact) are tailored to your exact head shape. Find out here how that has affected our safety stats.
This information is shared with every person whose head we scan, in a cool interactive and secure 3D viewer that also shows you what you’d look like with a HEXR on your noodle.
Here is mine if you’d like to gawp. (Don’t worry you are allowed to smile when getting scanned - I did not, only because this was the hundredth time I’d been scanned during testing!)
The next step is feeding these variables into what we call The Automation, a beastly algorithm that crunches numbers at a mind-numbing rate of 4 billion per second. The Automation considers each of the 30,000 scan points and how they holistically form your head shape until - fanfare! - out pops a 3D file of a bespoke helmet ready for printing.
Using multi-threading, multiple helmets are generated in parallel, each one denoted by a unique colour. (Sequence speed altered to liven up the inherently boring stream of code!)
Why else perfect fit matters
You now know how we capture 3D data and how we create a HEXR. But why exactly is going through all of this to generate the perfect fit so important? I touched on the primary reason 23 lines up (that number is probably wildly out on any computer other than my own) – the safety.
The perfect fit inside and out improves safety for a few reasons:
- Mechanical properties tailored to the object it’s protecting. When protecting your most valuable asset, every percentage improvement on energy absorption matters. Your head is a different size, shape, and mass to your mate’s head; why would we expect the same sized helmet to protect you equally?
- It sits where it’s meant to. Imagine if seatbelts came in one size. During an accident, there’s a good chance you’d be thrown around too much before the seatbelt did anything. A helmet that conforms to the contours of your head will always sit in the orientation that has been proven to protect it best.
- One less excuse to not wear a helmet. The best step to protect your head is wearing a helmet in the first place. I wear my HEXR far more than I’ve ever worn helmets in the past. The comfort means you can forget it’s there (I’m not kidding - we’ve got reviews from professional that say the same thing).
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