XmdvTool is a public-domain software package for the interactive visual exploration of multivariate data sets. It is available on all major UNIX/LINUX/MAC and Window platforms. XmdvTool is developed based on OpenGL and Tcl/Tk. It supports five methods for displaying flat form data and hierarchically clustered data: 1. Scatterplots 2. Star Glyphs 3. Parallel Coordinates 4. Dimensional Stacking 5. Pixel-oriented Display