Summary. We describe a system supporting the interactive exploration of threedimensional scientific data sets in a virtual reality (VR) environment. This system aids a scientist in understanding a data set by interactively placing and manipulating visualization primitives, e. g., isosurfaces or streamlines, and thereby finding features in the data and understanding its overall structure. We discuss how the requirement of interactivity influences the architecture of the visualization system, and how to adapt standard visualization techniques to work under real-time interaction constraints. Though we have implemented our visualization system to work with multiple types of data sets structures - cartesian, tetrahedral, curvilinear-hexahedral and adaptive mesh refinement (AMR) - we will focus on AMR grids and show how their inherent multiresolution structure is useful for interactive visualization.