Abstract: In this work, we explore the potential of combining virtual reality (VR) visualizations of data with physical models generated via rapid 3D prototyping to provide a new style of exploratory data visualization. Holding a physical rapid prototype model in one's hand can provide an immediate and more accurate understanding of a complex 3D form than can be provided via a computer display, even a head-tracked VR display. However, physical printouts are static and only show the bounding surface (the outside) of a 3D geometry. When working with many of today's scientific datasets, for example, analyzing results of high-performance simulations of cardiovascular fluid dynamics [Simon et al. 2010], scientists need to understand both a complex bounding surface for the data and multivariate volumetric data contained within it. We present the initial design of a new interface for exploring this type of data. Our goal is to combine the intuitive shape understanding made possible by physical 3D rapid prototypes with complementary VR visualizations of the data inside the printed geometry.