See-Through (ST) 2-Hand (2H) Arrow (AR) Vibration (VB) Figure 1: Visual feedback techniques investigated in our studies. ABSTRACTWe investigate visual feedback for virtual grasps, especially cues to improve behavior after real fmgers enter a virtual object. To date, such visual cues have usually been developed in an ad-hoc manner, with minimal or no studies that can guide selection. Existing guidelines are based largely on other interaction types and provide inconsistent and potentially-misleading information when applied to grasping. We compare several different visual feedback types including those most commonly seen for virtual hand interaction and with some novel visual aspects. The visuals were tuned in a pilot study, and our main study evaluated results in terms of objective performance (fmger penetration, release time, and precision) and sUbjective rankings. Performancewise, the most promising techniques all directly reveal penetrating hand configuration in some way. Subjectively, most techniques are better than simple interpenetrating visuals, with color changes being most promising. The results enable selection of the best cues based on the relevant tradeoffs. Results also provide a needed basis for more focused studies of specific visual cues and for better informing studies of multi modal feedback.

No abstract

No abstract

No abstract

This paper describes a real-time welding simulation method for use in a desktop virtual reality simulated Metal Inert Gas welding training system. The simulation defines the shape of the weld bead, the depth of penetration, and the temperature distribution in the workpiece, based on inputs from the motion-tracking system that tracks the position of the welding gun as a function of time. A finite difference method is used to calculate the temperature distribution, including the width of the weld bead and the depth of penetration. The shape of the weld bead is then calculated at each time step by assuming a semi-spherical volume, based on the width of the weld bead, the welding speed, and the wire feed rate. The real-time performance of the system is examined, and results from the real-time simulation are compared to physical tests and are found to have very good correlation for welding speeds up to 1,000 mm/min.