API Reference > geometry-core > Curve > CurveChainWithDistanceIndex > fractionToPointAndUnitTangent fractionToPointAndUnitTangent Method Returns a ray whose origin is the curve point and direction is the unit tangent. fractionToPointAndUnitTangent(fraction: number, result?: Ray3d): Ray3d Parameter Type Description fraction number fractional position on the curve result Ray3d optional receiver for the result.Returns a ray whose origin is the curve point and direction is the unit tangent. Returns - Ray3d Defined in core/geometry/src/curve/CurveChainWithDistanceIndex.ts Line 434 Last Updated: 13 June, 2024