The Vis5D system has been extended to support visual comparison of multiple numerical simulations. This is useful for ensemble forecasts, for cross-media simulations (e.g., weather, atmospheric chemistry, ocean physics and ground water flows), and for numerical experiments with controls. Multiple data sets may either be overlaid in the same 3-D window or visualized side-by-side spread sheet style. In the overlaid display, data sets with different spatial and temporal samplings are aligned in space and time. In the spread sheet style display, controls in different display cells may be linked (e.g., slices dragged through one disploay are dragged through all)