Techniques for creating interactive walkthroughs or visualizations of real-world environments. Such environments for which interactive walkthroughs may be created may comprise large interior spaces (e.g., buildings), wherein a space may comprise multiple rooms. The interactive walkthroughs may be photorealistic and rendered from arbitrary viewpoints at interactive rates. In one aspect of the invention, a technique for generating a visualization representative of an environment comprises the following steps. A dense set of image data is captured from the environment. The captured image data is compressed for storage. A portion of the compressed image data may then be decompressed so as to render a visualization representative of the environment from a selected novel viewpoint. Another portion of the image data may be prefetched and decompressed such that captured image data surrounding the selected novel viewpoint is available to be rendered. The visualization of the environment may then be rendered from the selected novel viewpoint.