Ph.D. Theses

Designing, Implementing, and Evaluating Intuitive and Interactive Lighting Simulation Tools

By Joshua Nasman
Advisor: Barbara Cutler
February 1, 2016

Tangible user interaction tools enable designers to use their hands to interface with computers in new and exciting ways. Three stages of interface development are necessary to create an intuitive and interactive tool: design, implementation and evaluation.

Architectural daylighting is the use of natural light in a space to improve energy efficiency, and allow interesting aesthetic choices. We have developed a tangible user interface for daylighting design that allows users to effectively evaluate the natural daylight in a space and iteratively improve upon designs. The interface allows users to model architectural spaces with small scale physical primitives and projects the simulated natural light into the space from six or more projectors surrounding the tabletop.

We conducted a series of user studies that revealed that designers found the language of the physical primitives to be simple, expressive, and powerful. Users gained significant intuition about daylighting, but experienced difficulties judging scale while using our early system. The observations from our user study shaped the evolution of the system features designed in this thesis. I present improvements that address the needs of designers including alternate visualizations to better communicate physical scale, overillumination, underillumination, and glare. The light simulation rendering algorithm in the system was replaced by a GPU photon mapping solution specifically adapted to allow lighting from multiple viewpoints and to gather light across areas of interest. An improved system architecture from a simple one machine configuration utilizes three desktop machines to run the complete system. The distributed architecture allows other applications besides daylighting such as an augmented reality game to be run on the tabletop system with minimal system modifications. The architecture provides the potential for many fun and educational tools to be developed.

Through user evaluations, implementation, and feature design, this thesis explores how to design an intuitive system and add valuable features to an existing interface. These features allow architects to view daylighting information and gain daylighting intuition in ways not available in traditional interfaces. The lessons learned from these explorations exemplify using good principles in designing and updating novel interfaces.

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