TractorBeam Selection Aids: Improving Target Acquisition for Pointing Input on Tabletop Displays


J. Karen Parker
Michael N. Nunes
Regan L. Mandryk
Kori M. Inkpen

Author Addresses: 

Faculty of Computer Science
Dalhousie University
6050 University Ave.
PO Box 15000
Halifax, Nova Scotia, Canada
B3H 4R2


This paper presents a comparison of several selection aids for TractorBeam input on tabletop displays. TractorBeam is a hybrid point-touch interaction technique for tabletop displays. Our previous research with the technique showed that while pointing input was preferred (over touch) by users of tabletop displays, it was slower than touch input for small distant targets, faster for large targets, and comparable in other cases. Drawing from previous work on improving target acquisition for various types of displays, we developed and tested three selection aids for improving selection of small distant tabletop targets: expanding the cursor, expanding the target, and snapping to the target. Our experiments revealed that all three aids resulted in faster selection times than no selection aid at all, with snapping to the target being the fastest. Additionally, participants liked snapping to the target better than the other selection aids and found it to be the most effective for selecting targets in our study.

Tech Report Number: 
Report Date: 
September 13, 2004
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