Authors:Dipl.-Ing. Boyan Mihaylov | Tutors: Dr.-Ing. Ferdinand Ludwig (IGMA), Dipl.-Ing. Tobias Schwinn (ICD) | Supervision: Prof. Dr. Phil. Gerd de Bruyn (IGMA), Prof. Achim Menges (ICD)
The dynamic and transforming nature of Baubotanik structures poses a challenge that is widely uncommon for the dominating realm of static structures in architecture. Faced with the problem of predicting the development of a constantly transforming tree structure, the planner needs to apply a suitable method that deals with the building as a continuous process rather than as a finalized object. An attempt to synthesize such a method in a coherent, structured planning tool was made during a studio project in the summer semester of 2013 at the University of Stuttgart. In it, specific principles relevant to growth and biomass distribution, which were already identified during previous research (Ludwig, 2012), were analyzed and interpreted as algorithmic logic and interconnected within a digital simulation tool. This tool was tested for validity on several typical cases, as well as on a large-scale architectural design proposal, in order to demonstrate its applicability for more complex design problems.
Whilst the majority of computer-aided tools in architecture are limited to predicting the development of a structure only up to its fabrication and assembly process, the aim of the Baubotanik-tool is to approximately describe the structure’s development beyond its initial setup. The global form and the topological network of tree segments can be strategically defined by the designer according to specific programmatic or structural requirements, after which the tool could be applied to predict qualitative outcomes from the structure’s growth, both in girth and in foliage. Thus, a potential design option could be tested in advance for critical parts or regions, that are bound to die or dominate over others as a result of their topological position or due to crown competition. An essential part of the developmental process of Baubotanik structures is the merging (inosculation/grafting) of mechanically connected tree individuals into a single living organism. Focusing on a relatively accurate girth growth prediction and a rather qualitative prediction of the crown development, the tool is primarily suited for providing relevant information for structural analysis such as the diameter of load-bearing segments in the tree structure. Secondarily, it could provide useful information about shading through foliage. It can also be used to simulate future outcomes in the case of unexpected or manipulated scenarios – for example, after a sudden damage of a tree segment or during a localized correction through crown-trimming. Following a straightforward mathematical model rather than complex agent-based systems, it is aimed at a more quantifiable prediction of the developing dimensions of the tree compound.
The process consists of several steps: Firstly, the initial geometric setup has to be defined and initial values for the segment cross-sections and the crown radii need to be set. Then, using an expanded version of the Resistance Model and the Pipe-Model, commonly used to illustrate the water transport in trees, an iterative process begins. It alternately calculates the currents via the nodal and loop equations derived from electromechanics and updates the crown sizes, calculating the survived volume after the spatial competition between the neighbors. After running the algorithm for a predefined number of steps, the absolute time for the development can be estimated by considering the produced biomass throughout the overall growth process.