This are the equations given to convert the new spring model to a classic mass, stiffness, damping model. mass = 1 stiffness = (2π ÷ duration)^2 damping = 1 - 4π × bounce ÷ duration, bounce ≥ 0 4π ÷ (duration + 4π × bounce), bounce < 0 The damping equation is wrong. This is what I worked out from playing with the spring model: The cleanest relation is to express the dampingRation (friction ÷ (2 × sqrt (stiffness × mass))) dampingRatio = 1 - bounce, bounce ≥ 0 dampingRatio = 1 ÷ ( 1 + bounce), bounce < 0 Then the damping becomes damping = ((1 - bounce) × 4π) ÷ duration, bounce ≥ 0 damping = 4π ÷ (duration × (1 + bounce)), bounce < 0