Nearest-neighbour projection ratio ⟨ℓ_3D⟩/⟨ℓ_2D⟩ as a function of SDR evaluated for fractal ensembles (D = 1.7–2.5, n_div = 2–4) at a fixed value of N = 200. Points and shaded bands show the mean and ±1σ scatter across configurations. The projection bias increases rapidly up to SDR ~ 10–20, beyond which it asymptotically approaches the intrinsic structural limit (𝒞_∞ ≈ 1.9–2.0). At a low SDR, beam blending dominates, merging close pairs and driving 𝒞 → 1, i.e. apparent isometry between 3D and 2D separations.