API Reference > geometry-core > CartesianGeometry > Vector3d > isParallelTo isParallelTo Method Test if this vector is parallel to other. isParallelTo(other: Vector3d, oppositeIsParallel: boolean = false, returnValueIfAnInputIsZeroLength: boolean = false): boolean Parameter Type Description other Vector3d second vector in comparison oppositeIsParallel boolean if the vectors are on the same line but in opposite directions, return this value. returnValueIfAnInputIsZeroLength boolean if either vector is near zero length, return this value. Returns - boolean Defined in geometry3d/Point3dVector3d.ts Line 1291 Last Updated: 11 June, 2024