In order to be able to understand the functionality of even small concurrent systems, visual and formally-based notations for their description are needed. The handling of complex systems additionally demands for notations offering adequate structuring capabilities. From a theoretical point of view the combination of Petri-Nets and object-oriented concepts is a promising approach in this area. Despite their potential, only few of the existing object-oriented Petri-Net proposals support the seamless development of systems ranging from high-level analysis to visual programming. This article introduces a set of essential properties for approaches in the area of object-oriented Petri-Nets and briefly surveys the common problems of existing work. Afterwards OOPr/T-Models, a novel approach intended to overcome the limitations of existing ones, are introduced. Their practical use as visual programming language for the description of (concurrent) object-oriented systems is shown with an example for the rendering of fractal images.