Plants are complex organisms, showing collective adaptive behavior. Plant behavior is often defined by shoot growth, yet root systems exhibit equally complex, less visible, behaviors. Roots have to navigate in a particular environment, while optimizing nutrient and water uptake as well as avoiding exposure to harmful elements. In this paper, we introduce an interactive, agent-based simulation model of root growth. It supports the exploration of the interplay of different root models within different environments. To this end, we resort to Swarm Grammars (SGs) which combine the interactivity of spatial agents with the generative perspectives of LSystems. We pursue a point-based representation of the environment due to its versatility with respect to modeling and rendering possibilities. SGs and point-based environments are combined in a simulation that enables interactions between a user, agents and the environment at runtime. We validate the model by recreating and analysing several established root model configurations, and validate the benefits of the interactive simulation by an expert interview.

Morphogenesis in biological systems is controlled by the parameters encoded in the genomes and rules of interaction between different components of the system and environment. Several methods are proposed for developing morphology of artificial structures. Some of them are inspired by embryogenesis in biological organisms. Others use more abstract generative encodings such as variances of L-systems. Our approach to morphogenesis is based on the distribution of a common resource between competing components of a growing system. The novel distributed controller called Vascular Morphogenesis Controller (VMC) is inspired by the growth process of plants and more specifically the competition between different branches for developing vessels and thus for further growth. The initial algorithm is introduced for modular robots. Here we use it to solve a maze.