Tracing means redrawing a paper contour by hand in a drawing program, usually point by point on top of a photo or a scan.
Tracing copies whatever distortion the photo already has. The camera angle and the lens both bend the outline, and neither is something the eye can correct while drawing. PatternScan Pro computes those out first and detects the contour itself.

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.