2. Related work
Smart devices have only recently been developed, but there are
many studies on pen gesture inputs (one-point touch) as touchenabled devices have been around since the 2000s. These concepts
fall under the concept of sketch-based modeling. There are several
methods of sketch-based modeling; the most efficient among them
can vary according to the shape of the target models, the method of
user interaction, and depending on several limitations [8]. Sketchbased modeling can be divided into two methods (see Fig. 1);
the first is gestural modeling, and the second is reconstructional
modeling