A Developmental Model for Generative Media Jon McCormack Centre for Electronic Media Art School of Computer Science and Software Engineering Monash University Clayton, Victoria 3800, Australia jonmc@csse.monash.edu.au Abstract. Developmental models simulate the spatio-temporal develop- ment of a complex system. The system described in this paper combines the advantages of a number of previously disparate models, such as timed L- systems and cellular programming, into a single system with extensive modeling flexibility. The new system includes the ability to specify dy- namic hierarchies as part of the specification, and a decoupling of cell de- velopment from interpretation. Examples in application areas of computer animation and music synthesis are provided. 1 Introduction We are interested in generalized models that simulate the continuous development of some complex system in space-time. This paper describes a new developmental sys- tem for the dynamic simulation of organic forms and processes. By decoupling the generative process from the generated output, dynamic models can be created in a variety of different application domains, including biological and botanical simulation, music composition, interactive animation, and computer graphics. The developmental system described in this paper is strongly influenced by related work in developmental modeling using L-systems, in particular parametric, timed and differential L-systems. The original formulation of L-systems by Lindenmayer in 1968 was a conceptually elegant, discrete, symbolic model of development in cellular biology [1]. In 1990, Lindenmayer and Prusinkiewicz published The Algorithmic Beauty of Plants, with an emphasis on three-dimensional, visually realistic models of herbaceous plants [2]. This introduced a number of variations and extensions to L- systems in order to overcome the discrete, symbolic nature of basic constructs such as D0L-systems 1 . Subsequent developments incorporated other continuous developmental control, such as the use of differential equations to model growth and signaling in modules [3] and the effects of environmental constraints [4]. More recent work uses Chomsky grammars in combination with interactive curve editing software to obtain greater visual modeling flexibility and control [5]. 1 D0L-systems are deterministic and context free. J. McCormack: "A Developmental Model for Generative Media", in M. S. Capcarrere, A. A. Freitas, P. J. Bentley, C. G. Johnson and J. Timmis (eds),Proceedings of the 8th European Conf. on Advances in Artificial Life, (ECAL 2005), Canterbury, UK, 5-9 September 2005, LNAI Vol 3630, Springer-Verlag, Berlin, Germany, ISSN: 0302-9743, ISBN-10: 3-540-28848-1, ISBN-13: 978-540-28848-0, pp 88-97.