Non-Photorealistic Rendering of Algorithmically Generated Trees

This work presents a novel rendering technique inspired by artistic approaches. Instead of trying to recreate the appearance of a traditional medium, such as charcoal or watercolor, this approach is a mixture of both photo-realism and abstraction. Artists use a process of abstraction to provide structural information about subjects that do not have clearly defined shapes, such as groups of leaves in a tree. For example, an artist will first use a color wash to approximate a group of leaves, then add detail on top of parts of this wash to indicate individual leaves. Similarly, we use an abstract shape that approximates the image of leaves clustered at the end of a branch. To prevent oversimplification, we add photo-realistic detail using a blending process. Inter-frame coherence is achieved by smoothly interpolating the abstract shapes as well as by the continuity inherent in the photo-realistically rendered detail