- Fluid dynamics simulation is often repeated while changing conditions, and therefore we need to compare a large amount of results. In order to compare results under different conditions, it is effective to overlap the streamlines generated from each condition in a single 3D space. Streamline is a curved line which represents a wind flow. This paper presents a technique to automatically select and visualize important streamlines suitable for comparison of the simulation results. In addition, we present an implementation to observe the flow fields in virtual reality spaces.