Screenplay Tension Curve — Story Structure Simulator

Every feature screenplay lives or dies on its shape: where the stakes rise, where they dip, and whether the climax actually lands harder than everything before it. This simulator turns that shape into a real 3D "story mountain" — a tube whose height and colour trace a mathematically modelled dramatic-tension curve across the full page count, built from Gaussian beats placed at the classic three-act turning points (inciting incident, midpoint, all-is-lost, climax). Drag the midpoint, dial the climax up or down, and switch between Slow Burn, Balanced and Rollercoaster pacing styles to see the curve reshape in real time, while live readouts track estimated runtime, the page where tension peaks, and the Act 2 average that flags a "sagging middle" — one of the most common notes a screenplay gets in professional coverage.