Prop kind.
OptionallengthFence segment length, metres.
Per-instance seed.
OptionalvariantVariant (round / square bales, rail / picket / stone fences).
Position (frame-local).
Ground height.
Yaw about up, radians (fences run along their local x).
Position (frame-local).
A prop to place (the same fields as threejs-props'
PropPlacement, so the list can be passed toPropsas is).