OpenAlea : A visual programming and component-based 1 software platform for plant modeling 2 3

15 As illustrated by the approaches presented during the 5 th FSPM workshop (Prusinkiewicz 16 and Hanan 2007, and this issue), the development of functional-structural plant models 17 requires an increasing amount of computer modeling. All these models are developed by 18 different teams in various contexts and with different goals. Efficient and flexible 19 computational frameworks are required to augment the interaction between these models, 20 their reusability, and the possibility to compare them on identical datasets. 21 In this paper, we present an open-source platform, OpenAlea, that provides a user-friendly 22 environment for modelers, and advanced deployment methods. OpenAlea allows researchers 23 2 to build models using a visual programming interface and provides a set of tools and models 24 dedicated to plant modeling. Models and algorithms are embedded in OpenAlea components 25 with well defined input and output interfaces that can be easily interconnected to form more 26 complex models and define more macroscopic components. The system architecture is 27 based on the use of a general purpose, high-level, object-oriented script language, Python, 28 widely used in other scientific areas. We briefly present the rationale that underlies the 29 architectural design of this system and we illustrate the use of the platform to assemble 30 several heterogeneous model components and to rapidly prototype a complex modeling 31 scenario. 32 33 Introduction 34