The commonly recognized weakness of modern object-oriented design and implementation methodologies lies in their superficial treatment of inter-object dynamics. This paper describes a software toolbox called ODYMOT that integrates a number of approaches to the problem of behavior modeling. In order to achieve design flexibility, a two-layer object design architecture is used that blends together object-oriented design concepts with those of high-level Petri nets. The Petri net representation creates an additional access layer of object architecture, providing meta-level object control with the sequencing of method execution. This modeling approach allows one, both mathematically and pragmatically, to achieve a more precise and flexible description and implementation of real-time and distributed models.