Try this:
New: Motion Blur and Anti-aliasing for Vertex Animation Materials
Materials that animate vertices using World Position Offset can now output accurate motion vectors. The motion vectors allow per-pixel motion blur from the procedural animation. Additionally Temporal Anti-Aliasing and Distance Field Ambient Occlusion can correctly reproject to prevent undesirable blurring.
Visualization of per-pixel velocities from a tree animated with World Position Offset.
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And how was the tree visualized?