There's another facet to this. Some athletic shoes have recently started using advanced "3D" knitting machines for the uppers. With traditional shoe making, th

There's another facet to this. Some athletic shoes have recently started using advanced "3D" knitting machines for the uppers. With traditional shoe making, there's waste when cutting the components of the upper from a sheet of material. But a knitted upper has essentially zero waste material, because it's created to the precise target shape. I.e. it's an additive manufacturing process like a 3D printer rather than a subtractive process.