Can a Shoe Be Sprayed Into Form?

In the world of performance footwear, most shoes are still made through multi-step processes involving cutting, stitching, gluing, and assembly—methods that are both labor-intensive and environmentally costly.

A new technology from Swiss brand On, called LightSpray™, proposes a different approach: spraying a shoe upper into existence using a robotic arm and a single thermoplastic filament.

Developed at On’s research lab in Zurich, LightSpray™ creates a form-fitting, laceless upper around a foot-shaped mold in about three minutes. The process is entirely automated, eliminates the need for adhesives, and results in a seamless structure. It’s a shift not just in materials or design, but in the underlying logic of how a running shoe is made.

A Single-Step Process

LightSpray™ operates through a robotic nozzle that spirals around a last (a foot-shaped mold), layering a thermoplastic thread that hardens into a breathable, stretchable upper. Because the process is digitally controlled, each upper can be customized in real-time without retooling, potentially allowing for made-to-order shoes in the future.

The first product using this method is the Cloudboom Strike LS, a carbon-plated racing shoe intended for elite long-distance runners. Though the performance specs include common industry ingredients—foam, carbon plates—the upper itself reflects a manufacturing experiment more than a design trend.

Environmental Context

By replacing multiple traditional components with a single sprayed material, On says the process reduces the carbon footprint of the upper by around 75%. There’s no stitching or glue, and less waste generated overall. But like many sustainability claims in the performance gear world, the broader environmental impact will depend on how scalable and recyclable the materials truly are over time.

Where It Shows Up

A prototype of the Cloudboom Strike LS was worn by marathon champion Hellen Obiri at the Boston Marathon and later highlighted during the 2024 Olympics in Paris. These public moments suggest On sees LightSpray™ not just as a lab experiment, but as a serious production method with broader implications for the industry.