Currently, it is possible to have two or more simultaneous touch
inputs (known as multi-touch input) using a capacitive touchscreen. Past pen-input methods were only able to accept one-point
inputs. Thus, the multi-touch method is more diverse and scalable.
As a result, there have been many studies on multi-touch modeling
in recent years . In 2012, Ranglani used a multi-touch
system for the manipulation of 3D models. He suggested a method
for operating and arranging 3D models using certain commands
such as move, rotate, and lift. Until recently, most multi-touch
studies have been limited to manipulation and navigation models
such as that in Ranglani’s research.