API Reference > geometry-core > CartesianGeometry > Vector2d > isParallelTo isParallelTo Method Test if this and other area parallel, with angle tolerance Geometry.smallAngleRadiansSquared. isParallelTo(other: Vector2d, oppositeIsParallel: boolean = false): boolean Parameter Type Description other Vector2d second vector for comparison. oppositeIsParallel boolean if true, treat vectors 180 opposite as parallel. If false, treat those as non-parallel. Returns - boolean Defined in core/geometry/src/geometry3d/Point2dVector2d.ts Line 510 Last Updated: 15 June, 2021