Set in an image-based model of St. Peter's Basilica, and featuring hundreds of steel spheres and falling monoliths, "Fiat Lux" presents an abstract interpretation of the conflict between Galileo and the church, drawing upon both science and religion for inspiration and imagery.

Here's some of the story of how image-based modeling, rendering, and lighting were used to create the animation "Fiat Lux" for both the SIGGRAPH 99 Electronic Theater and inclusion in the ACM SIGGRAPH "The Story of Computer Graphics", also premiering at SIGGRAPH '99. The film features a variety of dynamic objects realistically rendered into real environments, including St. Peter's Basilica in Rome. The geometry, appearance, and illumination of the environments were acquired through digital photography and augmented with the synthetic objects to create the animation. The film builds on the techniques of the animations "The Campanile Movie" and "Rendering with Natural Light" from SIGGRAPH 97 and 98.

Most image-based modeling techniques are only able to render the models as they originally appeared in the photographs. This makes it difficult to add new objects to the scenes, since adding such objects requires illuminating them properly and having them cast the appropriate shadows and reflections in the scene.

After finishing The Campanile Movie, I set out to try to be able to make photorealistic modifications to image-based models. The key to doing this Was to accurately record the illumination present in the environments that we model. Using a special high dynamic photography method (without it, real cameras don't have nearly the range to accurately record real-world illumination conditions), I was able to use measurements of real illumination in the world to illuminate synthetic objects - a technique called Image-Based Lighting. I presented this work in a paper at SIGGRAPH 98 and demonstrated the technique at last year's Electronic Theater with "Rendering with Natural Light", a short animation of a collection of ornamental spheres on a pedestal, illuminated by the light in UC Berkeley's Eucalyptus grove. The film also demonstrated using the measurements of real illumination to produce a variety of realistic effects of cinematography, such as soft focus, vignetting, and flare effects.

For this year's animation there were a number of new ways that I wanted to try to use this technology. For one thing, I wanted to show shadows and reflections in the scene based on real illumination, calculated without any synthetic light sources. I also wanted to render dynamic, moving objects into the scenes, causing us to refine our rendering techniques to increase their efficiency and frame to frame consistency. I wanted to combine image-based lighting with the techniques used in "The Campanile Movie" to create virtual camera moves through luminous spaces. Fourth, I wanted to show majestic environments with complex lighting, with sets of objects one could clearly only imagine being there. And finally, I wanted to use these techniques in an effort to tell a story.

The resulting piece, created in collaboration with Tim Hawkins, Westley Sarokin, H.P. Duiker, Tal Garfinkel, Jenny Huang, Christine Cheng, and Jonathan Bach, was "Fiat Lux". Set in an image-based model of St. Peter's Basilica, and featuring hundreds of gigantic steel spheres and monolithic falling dominos, it presents an abstract interpretation of the conflict between Galileo and the church, between science and religion, and between truth and superstition. Principal photography in the basilica was completed in just one hour, and the added objects and camera moves were rendered entirely in post-production. "Fiat Lux" -- Latin for "Let there be Light" -- seemed to resonate with both the scientific and religious themes of the piece, as well as the new technology used to create it. And "Fiat Lux" is the motto of the University of California at Berkeley to boot.