Step 1: Implementing Rotation of Joints

 

We first created a 3D model of a tree in Blender. The 3D model has 20 joints which can be bent to simulate movement of the tree. 

In Unity, we then applied a rotation to each joint depending on the acceleration of the wind according to these equations:

N = L x (MA)

Rotation Angle = N/R

N: Moment of a joint

L: Length of the tree

M: Mass of the part of a joint to the top of the tree

A: Acceleration of the wind

R: Elastic coefficient of a joint (joints closer to the top of the tree, will have a greater rotation angle)


More information about these equations can be found at:  https://www.sciencedirect.com/science/article/pii/S0097849306000835#bib22

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