Evaluating the effectiveness of occlusion reduction techniques for 3D virtual environments

Abstract

We present an empirical usability experiment studying the relative strengths and weaknesses of three different occlusion reduction techniques for discovering and accessing objects in information-rich 3D virtual environments. More specifically, the study compares standard 3D navigation, generalized fisheye techniques using object scaling and transparency, and the BalloonProbe interactive 3D space distortion technique. Subjects are asked to complete a number of different tasks, including counting, pattern recognition, and object relation, in different kinds of environments with various properties. The environments include a free-space abstract 3D environment and a virtual 3D walkthrough application for a simple building floor. The study involved 16 subjects and was conducted in a three-sided CAVE environment. Our results confirm the general guideline that each task calls for a specialized interaction-no single technique performed best across all tasks and worlds. The results also indicate a clear trade-off between speed and accuracy; simple navigation was the fastest but also most error-prone technique, whereas spherical BalloonProbe proved the most accurate but required longer completion time, making it suitable for applications where mistakes incur a high cost.

Exploring the design space of multiscale 3D orientation

“…BalloonProbe [Elmqvist 2005] is a technique whereby distractor objects in a cluster are pushed to the outside of a spherical force-field to make target objects visible. Subsequently, Elmqvist and Tudoreanu [2006] analyzed the effectiveness of two fish-eye view techniques and two BalloonProbe shapes. Elmqvist and Tsigas [2006] also suggested animating between parallel and perspective view projections to reduce occlusion effects of clustered objects.…”

Simple Guidelines for Testing VR Applications

“…We have researched and analyzed the state of the art in evaluations connected to VR in some of our previous work, (Koeffel, 2007;Koeffel, 2008). In particular, more than 30 representative literature works concerned with evaluation of VR displays have been analyzed, and 15 of them have been chosen for a deeper study (Bayyari & Tudoreanu, 2006;Christou et al, 2006;Cliburn & Krantz, 2008;Demiralp et al, 2006;Elmqvist & Tudoreanu, 2006;Fink et al, 2004;McMahan et al, 2006;Ni et al, 2006;Patel et al, 2006;Qi et al, 2006;Sutcliffe et al, 2006;Takatalo et al, 2008;Vinayagamoorthy et al, 2006;Wang et al, 2006;Wilcox et al, 2006). The analyzed papers represent a determined cross-section of the mostly treated areas in VR and are related to the analysis of different visual display technologies in VR applications.…”

“…In (Wang et al, 2006), Wang et al evaluate the effects of real world distraction on user performance in VR. The effectiveness of occlusion reduction techniques is investigated by Elmqvist and Tudoreanu in (Elmqvist & Tudoreanu, 2006). Using the results of an empirical study, Qi et al develop guidelines to ease the choice of display environment for specific volume visualization problems (Qi et al, 2006).…”

“…3. Counting (Bayyari & Tudoreanu, 2006;Elmqvist et al, 2006;Qi et al, 2006;Vinayagamoorthy et al, 2006;Wang et al, 2006). Among other tasks completed less frequently by the participants: estimation, prediction, search and observation.…”

An Occlusion-Reduced 3D Hierarchical Data Visualization Technique

“…In 3D visualization techniques we often cause occlusion among objects, and it often prevents the readability of visualization results. This Occlusion is an important problem [4] to be solved, to satisfy the above requirement by 3D visualization techniques.…”