Draping means pinning fabric into shape directly on a dress form. The piece taken off the form is then turned into a flat pattern.
The draped fabric piece can be photographed and digitized just like a paper pattern. The detour of tracing it onto paper first is not needed.

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.