The Motion in Place Platform was an infrastructure experiment which sought to provide a 'deep' mapping of reconstructed human movement. It was a collaboration between Animazoo, a Brighton-based motion hardware company, researchers from the University of Sussex's Informatics lab, digital humanities researchers at King's College London, and the University of Bedfordshire. Both 3D reconstruction and Virtual Reality (VR) in archaeology have been used to a great extent in the presentation and interpretation of archaeological sites in the past twenty years. However, there remains a predominant focus on their use as a means of illustration which, while enhancing the visual perception of the site, facilitates only passive consumption by the audience. There is little critical discussion in the literature of how 3D digital environments might aid our interpretation of the occupation of space or the usage of artefacts, and of what the evidential constraints that bind such interpretation. This paper reports on two linked experiments which sought to use motion capture technology to test the validity of digital reconstruction in exploring such interpretations, using domestic round house buildings of the British Iron Age. No such buildings survive physically, so interpretation about their occupation and usage is solely dependent on reconstruction and experimentation. Contemporary human movement was captured in a studio-based representation of a round house, and compared with comparable movements captured in an experimental reconstruction of the same environment. The results indicate significant quantitative variation in physical human responses to the two environments, which should help inform the practice of using 3D reconstruction for archaeological sites in the future.