3D self-gravitating gas: rho_t+div m=0, m_t+div(mv)+grad p=−rho gradφ, e_t+div(ev)+p div v=nu|grad u|^2, lapφ=G rho, p=gamma e. 100³, isolated (φ=0 at walls). Warm, mildly super-Jeans cloud with an initial solid-body spin Ω about z: gravity pulls in while angular momentum supports the equatorial plane — the cloud flattens into a rotating disc (z-slice = disc face-on; switch axis to x-slice to see it edge-on as a thin band). Ω=0 recovers the round collapse; raise Ω for a wider, longer-lived disc. Centre-row line plots on the z-slice (log scale): density, temperature, pressure, |potential|, |∇p|, ρ|∇φ|. Force balance: where ρ|∇φ| (gravity) overtakes |∇p| (pressure) the gas collapses. 3D threshold Γ>4/3 (gamma>1/3); no black hole (Newtonian).