Effects of Surface Properties on Haptic Perception of the Form of Virtual Objects

The problem studied was the potential effects of surface properties, such as hardness, texture and friction, on haptically perceived form of 3D virtual objects; more specifically, on the precision in judgments of the curvature of a spherical object. It was expected that curvature of a soft surface, as well as of a surface with texture and/or friction, would be more difficult to judge than a hard surface without friction and texture. The difference limen was determined under four conditions with different surface properties. The participants’ task was, with the help of a haptic display (a PHANToM), to judge which of two spherical surfaces was more curved than the other. The result was that only texture had a significant negative effect on the judgments. More textures have to be studied to see how generalized this result can be. Concerning hardness, the participants seemed to adapt their exploratory movements to this property.