Carassius: a simple process model editor

Process models of different types and graphs are commonly used for modeling and visualization of processes in information systems. They may represent sets of objects, tasks or events involved in process linked with each other in some way. Wide use of process models in various notations engenders necessity of software tools for creating, editing, and analysing them.
This paper describes the process model editor which allows for dealing with classical graphs, Petri nets, finite-state machines and systems of communicating automata. Additionally, the tool is armed with the following list of useful features: process simulation based on a Petri net token-based replay, import and export of process models in different persistent formats, various model layouts and other process visualization abilities. Moreover, Carassius is a modular tool which can be extended with additional process model notations, processing, import and export possibilities.
In the paper one can find a detailed description of a couple of layout algorithms already implemented in the tool. These algorithms for visualization of Petri nets and graphs can be used as a base point for further development of more refined process visualization approaches. Carassius might be useful for educational and research purposes because of its simplicity, range of features and variety of supported notations.