Evaluation of Alternative Label Placement Techniques in Dynamic Virtual Environments

This paper reports on an experiment comparing label placement techniques in a dynamic virtual environment rendered on a stereoscopic display. The labeled objects are in motion, and thus labels need to continuously maintain separation for legibility. The results from our user study show that traditional label placement algorithms, which always strive for full label separation in the 2D view plane, produce motion that disturbs the user in a visual search task. Alternative algorithms maintaining separation in only one spatial dimension are rated less disturbing, even though several modifications are made to traditional algorithms for reducing the amount and salience of label motion. Maintaining depth separation of labels through stereoscopic disparity adjustments is judged the least disturbing, while such separation yields similar user performance to traditional algorithms. These results are important in the design of future 3D user interfaces, where disturbing or distracting motion due to object labeling should be avoided.