Subramanian, SriramGutwin, Carl2008-07-272013-01-042009-08-262013-01-04200820082008http://hdl.handle.net/10388/etd-07272008-163725Interaction techniques that use the layers above the display surface to extend the functionality of pen-based digitized surfaces continue to emerge. In such techniques, stylus movements are constrained by the bounds of a layer inside which the interaction is active, as well as constraints on the direction of movement within the layer. The problem addressed in this thesis is that designers currently have no model to predict movement time (MT) or quantify the difficulty, for movement (steering) in layers above the display surface constrained by thickness of the layer, its height above the display, and the width and length of the path. The problem has two main parts: first, how to model steering in layers, and second, how to visualize the layers to provide feedback for the steering task. The solution described is a model that predicts movement time and that quantifies the difficulty of steering through constrained and unconstrained paths in layers above the display surface. Through a series of experiments we validated the derivation and applicability of the proposed models. A predictive model is necessary because the model serves as the basis for design of interaction techniques in the design space; and predictive models can be used for quantitative evaluation of interaction techniques. The predictive models are important as they allow researchers to evaluate potential solutions independent of experimental conditions.Addressing the second part of the problem, we describe four visualization designs using cursors. We evaluated the effectiveness of the visualization by conducting a controlled experiment.en-USMotor performanceVisualizationDigital table3D steeringLayerstext