The author explains how the 3D illusion works by controlling the curvature of reflecting surfaces. They mention that the glint of light seen by the eye is actually coming from a point in 3D space. Each mirror used in a typical specular hologram has a unique doubly-curved shape to create the illusion without distortion. The author also discusses the use of differential geometry and combinatorial optimization in shaping and multiplexing the optical surfaces. They highlight the role of optimization in the artistic side of the endeavor, where they “sculpt” the scene and create the outlines, shadings, and textures of the surfaces.
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