overlay
Type-erased per-agent velocity/force samples for the animation overlay (G10), the 3D analog of Dynamics.overlaySample. NaN marks an uncaptured component.
Samples are flattened to the x–y plane, matching how ContinuousVolume.placeAt emits 3D positions: the vector overlay event carries no z channel, and the renderer draws in 2D. The z components of velocity and net force are therefore dropped here rather than silently mis-drawn.