<title>Evaluation of pointing techniques for ray casting selection in virtual environments</title>

Abstract

Various techniques for object selection in virtual environments have been proposed over the years. Among them, the virtual pointer or ray-casting is one of the most popular method for object selection because it is easy and intuitive to use and allows the user to select objects that are far away. Variants of the virtual pointer metaphor include the Aperture [5], Flashlight [3], and Image plane method [fl as categorized as such by [10]. In a monoscopic environment, these methods are essentially 2D interaction techniques, as the selection is made effectively on the image plane. Such a 2D based selection (or more generally, interaction) method has an added advantage in that it can find many good uses in 3D environments ranging from a simple 2D oriented subtask (object selection on a constrained surface, menu selection) to a siutation where a whole 2D application (e.g. sketching tool, desktop manager) is embedded in the 3D environment. In this paper, we experimentally compare the performance of four different virtual pointer implementations, namely, the direct image plane selection, head-directed pointer, hand directed pointer and head-hand directed pointer. The experimental results revealed that the direct image plane selection produced the best performance among the four in terms ofboth task completion time and the pixel-level pointing error.

Efficient Structure-Aware Selection Techniques for 3D Point Cloud Visualizations with 2DOF Input

“…For 3D data, raycasting selection techniques (e. g., [1,18,25,36]) are common in virtual environments that range from desktop VR to CAVEs; for true volumetric displays similar techniques are used [10]. Raycasting is frequently employed because it can be operated at a distance, is fast, and is easily understandable [21].…”

An investigation of pointing postures in a 3D stereoscopic environment

“…The results of the Borg Scale in our experiment indeed showed that participants reported more muscle fatigue with gaze-directed than with hand-directed pointing. The influence of muscle fatigue on the accuracy of hand placement has been supported by Lee et al (2003). Additionally, Bowman et al (2002) mentioned that hand tremors may influence the precision of target selection with the ray casting method and termed this phenomenon the "Heisenberg effect".…”

“…The muscle fatigue would have reduced the precision and speed of the pointing performance. Several previous studies (Bowman et al, 2002;Gallo and Minutolo, 2012;Lee et al, 2003) have pointed out the problem of tremors in precise pointing tasks. The results of the Borg Scale in our experiment indeed showed that participants reported more muscle fatigue with gaze-directed than with hand-directed pointing.…”

Development of a vision system for an intelligent ground vehicle

“…Ray-casting is scalable, however computationally expensive 11 , but its simplicity lends its application well for applications ranging from virtual navigation to large intelligent ground vehicles such as with the DARPA Urban Challenge 12 . A complete discussion of all of the vision applications of ray-casting is out of the scope of this paper; however, a few of the vision applications where ray-casting algorithms have been applied include navigation of virtual environments such as with computer games 13 , pointer techniques 14 and medical applications where CT or MRI scans provide the virtual landscape 15 to navigating actual 3D environments such as with intelligent ground vehicles 2,12,16 . In robotics, ray-casting algorithms are typically used like a virtual LIDAR scanning the sensor collected information such that either a 2D or 3D map can be generated from which navigation decisions can be made 2, 16 ; in our application, however, we have applied ray-casting to find the openings in the sensory data where our robot can most easily pass through the obstacles.…”