Interactive Modeling Techniques for Digital Twin Representation of Trees

Trees are among the most complex and visually captivating natural forms, playing a critical role in applications ranging from digital content creation and urban planning to ecosystem simulation and digital forestry. In this thesis, we present a unified framework for 3D tree modeling that integrates interactive procedural approaches, a novel volumetric representation, and the physics-based simulation.

Our approach extends traditional tree modeling by incorporating both above-ground branching structures and the often-overlooked root systems, capturing their coordinated development through a biologically inspired process. We introduced long-distance signaling process to emulate the natural exchange of resources between the shoot and root systems. By simulating the transport of growth regulators and nutrients, this mechanism establishes a dynamic feedback loop where environmental changes such as variations in light or mechanical stress affect both shoot and root system of the entire tree.

Another key innovation of our work is the strand-based representation, which models each branch segment as bundles of fixed-size volumetric cylindrical splines. This representation enables us to capture the secondary growth including twisting, bending, and the formation of complex branch bifurcations, offering a more detailed and realistic depiction of tree morphology than conventional skeletal graphs. Coupling with the volumetric model, we developed an interactive modeling system equipped with intuitive editing tools that empower users to directly intervene in the tree development process. This approach not only ensures that the resulting trees reflect natural diversity and maintain biological plausibility, but also makes the process highly customizable and controllable.

Furthermore, by integrating Cosserat rod physics, our framework simulates the dynamic mechanical behavior of trees under natural forces. This physical simulation captures branch deformations, fractures, and structural damage, delivering animation-ready models that respond realistically to environmental stimuli. Overall, our framework advances the state-of-the-art in digital tree modeling, providing a comprehensive tool chain for generating, editing, and simulating realistic trees for a wide range of applications.