Same waterfall as the 3D scene, driven from the side by the real kinematics instead of a fixed particle script:
- Free fall — the crest speed v₀ is small, so the vertical impact speed follows v(s) = √(v₀² + 2gs); fall time solves s = v₀t + ½gt² for the current cliff height.
- Continuity tapering — cross-section area A(s) = Q / v(s), so a fixed discharge Q makes the curtain visibly thin out as it accelerates downward, exactly like a tap stream.
- Overhang launch — a protruding ledge gives the water a horizontal exit speed v₀ₓ, so it leaves the cliff on a real parabola (x = v₀ₓ·t) instead of dropping straight down the rock face.
- Reynolds number — Re = v·Dh/ν with water's kinematic viscosity (ν ≈ 1.0×10⁻⁶ m²/s) confirms the flow is turbulent at any realistic scale, which is why natural waterfalls are never laminar sheets.
- Wind — the falling curtain is too heavy to steer, but the low-mass spray and mist above the pool drift and bend visibly with crosswind, just as real waterfall mist does.