Matthew McDonald Supervisors: Bruce H. Thomas & Ross T. Smith

Outline  Introduction  Motivation  Research Question  Methodology  Analysis  References  Questions

Introduction Spatial Augmented Reality (SAR): A branch of Augmented Reality where projectors are used to change the appearance of objects Has practical applications in education, entertainment, collaboration, industrial design, and manufacturing

Introduction Mahl-Stick: A traditional tool to support the brush hand in painting Works by transferring control of the brush away from the shoulder, elbow and wrist towards the fingers image from reillybrennan.com

Motivation  Drawing lines is an integral part of the creative process. Drawing accurately and repeatedly can be difficult and tiring  SAR has a wide variety of applications. Input devices and methods are needed; props and gestures are preferred  Pointing, clicking from one place to another, and Steering, drawing along a surface from one place to another, are ubiquitous interaction methods

Research Question What is the effect that a mahl-stick has when performing simple pointing and steering tasks in AR applications when using a stylus?

Research Question Sub-Questions:  How do novice and experienced users compare when using a mahl-stick?  What learning effect is observable? An artefact of this research is a new SAR input device

Methodology  The two tasks, pointing and steering, are completed by participants simultaneously, both with and without the use of a mahl-stick  Tasks assigned to participants in random order

Methodology  A 3 x 3 array is projected on a flat vertical surface in front of the participants

Methodology Pointing Tasks:  One circle will be highlighted. When user ‘clicks’ this circle with stylus, another circle will be highlighted. User is to ‘click’ the second circle as quickly as they can

Methodology Steering Tasks:  One circle will be highlighted. When user ‘clicks’ this circle with stylus, a tunnel to another circle will be highlighted. User is to draw within this tunnel to the other circle

Analysis  Pointing Task: Use Fitts’ Law, a quantitative method for comparing input devices  Steering Task: Use the Steering Law, derived from Fitts’ Law by differential calculus

Analysis Questionnaire:  Record participants preference for the use of the mahl-stick in both pointing and steering tasks, and how well they think they performed with them  Also acquire knowledge about their prior experience with mahl-sticks

References  Raskar, R, Welch, G & Fuchs, H 1998, ‘Spatially Augmented Reality’, IEEE First International Workshop on Augmented Reality, pp  Marner, MR, Smith, RT, Porter, SR, Broecker, MM, Close, B & Thomas, BH 2011, ‘Large Scale Spatial Augmented Reality for Design and Prototyping’, Handbook of Augmented Reality, pp  Faconti, G & Massink, M 2007, ‘Analysis of Pointing Tasks on a Whiteboard’, Interactive Systems. Design, Specification and Verification. Lecture Notes in Computer Science, vol. 4323, pp  Accot, J & Zhai, S 1997, ‘Beyond Fitts’ Law: Models for Trajectory-Based HCI Tasks’, CHI ' 97 Proceedings of the ACM SIGCHI Conference on Human Factors in Computing Systems, pp  Zhang, X, Zha, H & Feng, W 2012, ‘Extending Fitts' Law to Account for the Effect of Movement Direction on 2D Pointing’, CHI ' 12 Proceedings of the SIGCHI Conference on Human Factors in Computing Systems, pp

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