The current practice of modelling trees in daylight simulations is to ignore its complex interactions with light and model them as spheres, cones, or cylinders with an assumed reflectance or transmittance value. Trees modulate light, create speckled shadow patterns, and depending on their colour reflect light differently. In this research project, we proposed a low-cost method to measure onsite transmittance characteristics of a tree using hemispherical photography and image processing. The transmittance characteristics called the gap percentage is used to generate a 3D primitive tree crown model that mimics the distribution of leaves and gaps of the measured tree. The proposed model, when used in daylight simulation platforms such as Radiance, predicts vertical light transmittance and creates shadow patterns similar to the measured tree crown.
To view and use the code for tree generation go to our Github repository To read more about the methods used to develop the model read our published paper.