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🎯 Match the Frequency
A 3-story building. A target natural period. Your only lever is the story stiffness — tune it until the building's own fundamental period matches the target. Real modal eigenvalue physics, the same engine behind the Mode Shape Explorer simulation, no faking it.
Building
3 equal stories, 200 t mass each
Uniform story stiffness (all floors equal)
Target Period T₁
0.400 s
Your Stiffness
Live Result
—
Your Period T₁
—
% Error from Target
This game runs the exact same eigenvalue solver
(
engine/dynamics.js → eigenSolve) verified elsewhere on this
platform — cross-checked against an independent Python (NumPy) calculation for a
3-story building, matching to 5 decimal places in both frequency and mode shape ratio
before it was ever used in a game or simulation.Method
ModelLumped-mass shear building: each story is a mass connected to the next by a story stiffness — classic MDOF idealization (Chopra §9).
SolverInverse power iteration with M-orthogonal deflation to extract the fundamental mode from [K]{φ}=ω²[M]{φ}.