API Reference > geometry-core > Curve > Arc3d > quickEccentricity quickEccentricity Method Return a quick estimate of the eccentricity of the ellipse. The estimator is the cross magnitude of the product of vectors U and V, divided by square of the larger magnitude for typical Arc3d with perpendicular UV, this is exactly the small axis divided by large. note that the eccentricity is AT MOST ONE. quickEccentricity(): number Returns - number Defined in curve/Arc3d.ts Line 244 Last Updated: 11 June, 2024