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Epicycloid & Cardioid Simulator

Circle A rolling without slipping around fixed Circle B

Cardioid (k = 1.00) 60 FPS Engine
Angle θ (Orbit): 0.0°
Angle φ (Self): 0.0°
Point P(x, y): (0, 0)
Ratio (k = r_B / r_A): 1.00
Circle B (Fixed, r_B) Circle A (Rolling, r_A) Epicycloid Path
Speed: 1.0x

Circle Radii Parameters

Circle A Radius (r_A) 60 px
Circle B Radius (r_B) 60 px
Preset Configurations:

Display Settings

Mathematical Mechanics

An Epicycloid is traced by a point $P$ on a circle of radius $r_A$ rolling without slipping around a fixed circle of radius $r_B$.

Generalized Equations
x(θ) = (r_B + r_A)cos θ - r_A cos((1 + r_B/r_A)θ)
y(θ) = (r_B + r_A)sin θ - r_A sin((1 + r_B/r_A)θ)
No-Slip Rotation Condition
φ = θ · (1 + r_B / r_A)