There’s nothing like the mesmerizing view of branches dancing in the wind. Wind brings a tree to life. The wind system uses shape keys, which are fast and compatible with most 3D software. Calculating wind shapes and playing the animation in your viewport are both surprisingly fast, especially when stored in an Alembic file.
To add wind to your tree, go to the Wind panel and simply click Animate. The tree is animated through a sequence of wind shapes. Wind shapes are built from two components, directional wind and turbulence. Both use the already rock-solid bend algorithm, but instead of bending to gravity the tree now bends with the wind – with varying intensity over time.
Secondary motion caused by turbulence is perhaps the most believable. Whereas the first step is more obvious in strong winds, this step is already present in a slight breeze. It simulates the lifting of leaves. By randomizing the leaf weight of each branch over time, the tree starts dancing in the wind.
Wind blows from one of four directions – West, North, East or South. You can also select two of these directions to get the in-between direction.
Key frames for each wind shape are 2 frames apart. The Grove adds additional key frames at the beginning and end to make the animation loop forever. An animation with 50 wind shapes will loop seamlessly every 100 frames. When exporting to Alembic, be sure to match this frame range.