API Reference > geometry-core > Curve > Arc3d > fractionToPointAnd2Derivatives fractionToPointAnd2Derivatives Method Construct a plane with origin at the fractional position along the arc x axis is the first derivative, i.e. tangent along the arc y axis is the second derivative, i.e. in the plane and on the center side of the tangent. If the arc is circular, the second derivative is directly towards the center fractionToPointAnd2Derivatives(fraction: number, result?: Plane3dByOriginAndVectors): Plane3dByOriginAndVectors Parameter Type Description fraction number result Plane3dByOriginAndVectors Returns - Plane3dByOriginAndVectors Defined in curve/Arc3d.ts Line 331 Last Updated: 12 June, 2024