The Brannock devicethat sliding metal gadget used in shoe stores to measure the dimensions of your feetwas invented 100 years ago this year.But footwear fitting hasnt really gotten more advanced since, says Dan Cataldi, founder and CEO of custom insole maker Groov. For most people, it still comes down to finding shoes by style and size, taking a few steps in them, and hoping for the best. And when it comes to insoles, the part of the shoe that you actually walk on, people with medical issues and professional athletes might get custom orthotic inserts fitted by a doctor, while most people make do with what comes in their shoes or, in a pinch, a cushioning insert from the drugstore.[Photo: Groov]Groov is designed to bridge that gap, using an app that lets customers scan their own feet and footwear at home with their iPhone cameras so it can build 3D models of their two feet and understand the shapes of their shoes. Then, the companys machine learning algorithms can design a variety of styles of insoles for each customer.For me, the whole notion of Groov is taking something that should exist within footwear and bringing it into footwear, Cataldi says. If youve got to go see a clinician, if youve got to make an appointment, thats not footwear.Options include the Plush, an everyday cushioning model designed for comfort, and a high elasticity model designed for athletes, known as the Response model.Here we replace the soft, shock-absorbing, low-elasticity cushion with a high-elasticity, more explosive cushion for a quick first step, and I blast off in each step, he says.Theres also the Luxe, a more discreet replacement for built-in insoles for shoes like high heels, designed to be thin enough to stick into the shoe without being visible when the shoes are worn.[Photo: Groov]Groov insoles typically arrive within a few days, engraved with the customers name or another chosen nickname. If customers want to order more or try another style, like switching from the regular cushioning model to the athletics-focused variety, they can do so from the app. Customers are likely to want to retake their scans every year or two, or if they have reason to believe something has changed in their feet, and they can scan new shoes or the shoes existing insoles to order Groov insoles adapted to a particular pair, Cataldi says.Key to the easy customization is the TrueDepth camera system in the iPhone thats used for FaceID logins. The camera projects, then captures, a grid of invisible infrared dots, used in the FaceID system to create a unique model of the face and by Groov to similarly understand the contours of the foot.[Image: Groov]What that enables us to do is bypass any need for a clinical visit if its a non-medical situation, and get all of the data with millimeter-level precision, he says.And replacing that clinical visit with a brief, at-home foot scan means reaching a wide audience whod simply never think of getting inserts from a doctor. After all, Cataldi says, his own father is a chiropractor who provides orthotic inserts for patients and wore them himself, but even as a young athlete, Cataldi thought the medicinal-seeming devices felt like overkill.From Groovs perspective, being able to create insoles on demand is also an advantage, since theres no inventory that has to sit around company warehouses or on retailer shelves. But the company did in December do pilot pop-ups in Nordstroms mens and womens departments in Manhattan, where Groov was able to scan dozens of customers feet in-store.Future retail collaborations may be in the works, Cataldi says, and the company is also in talks with footwear companies about potential partnerships. Deals with e-commerce companies to integrate the technology into their shopping experiences might also be in Groovs future, he says, and for now the company is promoting the technology through social media, with athletes and others already highlighting their use of the inserts on Instagram.Another happy customer, Cataldi says, is his own father. While he still advocates orthotic inserts for patients who need them, hes switched away from them himself.Now, he wears Groovs, Cataldi says.