3D knitting machine builds solid shapes with flexible stitch control

Researchers at Cornell and Carnegie Mellon University have developed a prototype knitting machine capable of creating solid, three-dimensional objects rather than traditional flat fabric sheets. Unlike conventional knitting, which forms continuous yarn loops in a single plane, this machine adds stitches in multiple directions—including forward, backward, and diagonal—allowing it to build complex layered shapes with variable stiffness. The system operates similarly to a 3D printer, constructing objects layer by layer and providing precise control over both structure and texture. Central to the design is a 6×6 array of needles with 3D-printed double hooks that can knit or purl independently, guided by custom digital code that generates stitch patterns tailored to specific shapes. Although still in early development and facing challenges such as dropped loops and slow operation, the prototype has successfully produced small 3D forms like a C-shaped object and a pyramid, demonstrating its ability to handle curves, layers, and overhangs. The researchers see potential for scaling up the technology by increasing needle count