A Sketch Interpreter System with Shading and Cross Section Lines
Kunio KONDO, Haruki Shizuka, Weizhong Liu, Koichi MATSUDA · 2005
Abstract. We present a sketch interpreter system with shading and cross section lines for 3D freeform design. The input strokes are classi¯ed into three types: outlines (contour lines), shading lines and cross section lines. The outline is used to generate the basic rounded shape. The shading lines and cross section lines are used as control lines that are drawn inside the contour to modify the 3D shape. In order to e®ectively extract 3D information from the shading and cross section lines, we analyze di®erent representations and deformations of the shading and cross section lines and classify them into three cases: convex, concave and `upheaving'. Each deformation is drawn by hand and transferred to a 3D shape according to the rules proposed in this paper. We evaluate our sketch interpreter system for various objects from concept sketches and present our results.