| Tree simulation is one of the hot topics in computer graphics and virtual reality in recent years. Works in this area mainly focus on the simulation of tree branches, leaves and barks, while little attention has been paid on the tree’s geometric detail simulation. As an important geometric detail, the tree knot is formed from the missing of a branch, which happened either naturally or by artificially pruning. Simulations with different forms of tree knots can enhance the realism of virtual trees. From the perspective of timber production, tree knots have significant impact on the quality and utilization of wood.In this paper, based on the photos of tree knots, we analyze morphological characteristics of tree knots, classify tree knots into three types:bowl, snag bowl, and tuber, and set parameters for each tree knot. We study on parametric modeling approach for them, as well as the texture synthesis method for the intersected geometries of the knot and the branch, and implemented an interactive system of tree knots modeling and texturing. The experimental results show that, tree knots can be modeled conveniently with the system, and the tree with tree knots look more natural and realistic. Furthermore, the work can be used for the wood quality evaluation in the field of wood science. |
