This paper describes, Napkin Sketch, a novel 3D sketching
interface which attempts to mimic the qualities of conventional
sketching medium and tools both in terms of physical properties
and interaction experience. A portable tablet PC is used as the
sketching platform, and mixed reality techniques are employed to
allow 3D sketches to be created on top of a physical napkin.
Intuitive manipulation and navigation within the 3D design space
is achieved by visually tracking the tablet PC with a camera and
mixed reality markers. For sketch input, we improve upon the
projective 3D sketching approach with a one stroke plane creation
technique. This coupled with the hardware interface produces a
fluid and freeform sketching experience. Sketch recognition is
also integrated as an alternative method for 3D sketch input,
providing users the ability to quickly instance existing 3D models.