Exploring the Impact of Size and Input Mechanism for Using Touch-Based 2D Input in VR

Considering the lack of evaluation of the human factors of 2D touch input devices in VR, this paper explores the impact of touch device size and input mechanism on target selection performance from an ergonomic perspective. Through pilot experiments, two key factors, “touch device size” and “input mechanism,” were identified, and a VR interaction prototype based on smartphones and RGB-D fingertip tracking was constructed. In the formal experiment, we evaluated three sizes (3-inch, 5-inch, 7-inch) and three mechanisms (touch, release, lift-and-tap) across three representative tasks (target acquisition, teleportation navigation, text entry), measuring completion time, error rate, and NASA-TLX. Results demonstrated the 5-inch size paired with the release mechanism achieved the best tradeoff. Combined with Fitts’s law and the NTMR model, advantages in thumb comfort zone, C-D ratio matching and feedback rhythm were revealed. The study provided an empirical basis and engineering suggestions for 2D touch input in VR.