We report on a visualization system that has been implemented to study cellular events which regulate morphogenesis of large organs or whole embryos. For data acquisition the recently established system “Huge Image ” is employed. Each resulting image of an entire histological section is loaded into AutoCAD for manual contour creation and cytological diagnosis. In a subsequent step an automatic procedure detects and repairs contour artifacts in order to provide clean contour data. A modified version of Boissonnat's reconstruction algorithm is used to create 3D models from contour data. The user is allowed to choose from different modes for appropriate visualization of surfaces and data resulting from cytological diagnosis.