Ultrasound mid-air haptic interfaces are ideal for displaying tactile geometries, and can thus provide tangible sensations for 2D and 3D virtual shapes in human-computer interaction applications. Spatial and temporal sampling parameters, such as e.g. the number of points sampled on a shape, impact user’s perception of a given shape. The sampling strategy is thereafter defined as a combination of a spatial discretization of a shape and a set of rules for the temporal display order of the resulting points. This paper investigates the influence of sampling strategies on a user’s ability to differentiate arc curvatures.