A new formalism has been developed to combine the representation of contour levels in arbitrary planes with the visualization of chemical properties as color-coded molecular envelopes or as isovalue rendered surfaces. This tool, which is characterized by a totally interactive and user-friendly input, has been integrated within our basic molecular graphics package MOLEKEL, which is used for molecular modeling applications on- graphics workstations. After an overview of the design and practical implementation of this development, several applications are presented which underline its flexibility and utility in modeling the structure and reactivity of various chemical systems, ranging from pyrrole to Cr(benzene)(CO)₃ and C₆₀ fullerene derivatives.