A projector casts the pattern onto fabric or a cutting table at full size. You cut along the projected lines instead of printing and taping the pattern together.
Projecting needs a file that is to scale. A digitized paper pattern projects just like a digital pattern you bought.

Digitize sewing patterns without tracing.
Test PatternScan Pro free for 14 days with the full feature set. You need your smartphone, a printer and one pattern you always wanted digital.