VisuSimple: An interactive visualization utility for scientific computing. In this work we describe an easy to use and easy to modify open-source program that was developed for the needs of several projects in the SFB 359. The utility is based on the powerful open-source visualization toolkit VTK, the de factoindustry standard for visualization. It is an interactive visualization and graphics/movie-generation utility for multicomponent 2D- and 3D-data in the VTK-format. The data is the result of numerical computations such as e.g. computational fluid dynamics or computational structure mechanics. The main features of VisuSimple are shown based on examples.