This paper describes the design, operation, anddemonstration of the Solar Heliodon, a novel mechanicalinstrument developed to enable automated simulation ofinterior daylighting conditions with physicalarchitectural models using the sun as a light source. Anexperiment involving two physical models, one withangularly-selective complex fenestration and the otherwith a holographic window film, is performed toillustrate the applicability of the instrument for enablingsubjective and objective human-factors evaluation ofoptically complex daylighting design concepts. Benefitsand limitations relative to contemporary computationalapproaches to model generation, simulation, andevaluation are discussed.