Prediction of Graphic Interaction Time of Virtual Reality System Based on Improved Fitts' Law

This paper attempts to evaluate the click efficiency of different graphic designs of the virtual reality (VR) system for shipbuilding in a shipyard. For this purpose, a prediction method for the completion time of pointing tasks in a VR was proposed based on the probabilistic Fitts' law, and a selection model was constructed for targets in arbitrary shape in VR. According to the design requirements of VR interfaces, the authors considered the influence of target shape on task completion time, constructed the relationship between hit probability and the index of difficulty (ID) of the task, and took the target center as the center point of the function to be integrated, thus defining the probabilistic Fitts' model in VR scenes. Next, Experiment 1 was designed to compute the constant terms of probability function P(HIT) in the improved probabilistic Fitts' model; Experiment 2 was designed to calculate the constant terms of prediction function in the improved model. Int his way, the improved probabilistic Fitts' model was completed. Finally, our model was validated and evaluated by the actual pointing task of the shipbuilding VR system of a shipyard. The results show that our model can predict the task completion time well under VR scenes. The research provides effective guidance for designers to optimize the interface layout in a VR environment, and optimize the user experience of interface interaction.