An evaluation of menu properties and pointing techniques in a projection-based VR environment

We studied menu performance for a rear-projected VR system. Our experiment considered layout (pie vs. linear list), placement (fixed vs. contextual), and pointing method (ray vs. alternatives that we call PAM: pointer-attached-to-menu). We also discuss results with respect to breadth (number of menu items) and depth (top-level and child menus). Standard ray pointing was usually faster than PAM, especially in second-level (child) menus, but error rates were lower for PAM in some cases. Subjective ratings were higher for ray-casting. Pie menus performed better than list layouts. Contextual pop-up menus were faster than fixed location.