Reaching for objects in VR displays: Lag and Frame Rate
Abstract
This article reports the results from three experimental studies of reaching behavior in a head-coupled stereo display system with a hand-tracking subsystem for object selection. It is found that lag in the head-tracking system is relatively unimportant in predicting performance, whereas lag in the hand-tracking system is critical. The effect of hand lag can be modeled by means of a variation on Fitts' Law with the measured system lag introduced as a multiplicative variable to the Fitts' Law index of difficulty. This means that relatively small lags can cause considerable degradation in performance if the targets are small. Another finding is that errors are higher for movement in and out of the screen, as compared to movements in the plane of the screen, and there is a small (10%) time penalty for movement in the Z direction in all three experiments. Low frame rates cause a degradation in performance; however, this can be attributed to the lag which is caused by low frame rates, particularly if double buffering is used combined with early sampling of the hand-tracking device.
Department
Center for Coastal and Ocean Mapping
Publication Date
12-1994
Volume
1, Issue 4
Journal Title
ACM Transactions on Computer-Human Interaction (CHI)
Pages
331-356
Publisher Place
New York, NY, USA
Publisher
Association for Computing Machinery (ACM)
Digital Object Identifier (DOI)
10.1145/198425.198426
Document Type
Journal Article
Recommended Citation
C. Ware and R. Balakrishnan, "Reaching for objects in VR displays: Lag and frame rate," ACM Transactions on Computer-Human Interaction, vol. 1, no. 4, pp. 331–356, Dec. 1994.