API Reference > geometry-core > Curve > Loop Loop Class A Loop is a curve chain that is the boundary of a closed (planar) loop. see Curve Collections learning article. Extends CurveChain Methods Name Description constructor(): Loop Test if other is an instance of Loop announceToCurveProcessor(processor: RecursiveCurveProcessor, indexInParent: number = -1): void invoke processor.announceLoop(this, indexInParent) cloneEmptyPeer(): Loop Create a new Loop with no children cloneStroked(options?: StrokeOptions): AnyCurve Create a loop with the stroked form of this loop. dgnBoundaryType(): number Return the boundary type (2) of a corresponding MicroStation CurveVector dispatchToGeometryHandler(handler: GeometryHandler): any Second step of double dispatch: call handler.handleLoop(this) isSameGeometryClass(other: GeometryQuery): boolean test if other is a Loop create(...curves: CurvePrimitive[]): Loop Static Create a loop from variable length list of CurvePrimitives createArray(curves: CurvePrimitive[]): Loop Static Create a loop from an array of curve primitives createPolygon(points: Point3d[] | IndexedXYZCollection): Loop Static Create a loop from an array of points Inherited methods Name Inherited from Description checkForNonLinearPrimitives(): boolean CurveChain return true if the curve collection has any primitives other than LineSegment3d and LineString3d clone(): undefined | CurveCollection CurveChain Return a deep copy. cloneTransformed(transform: Transform): undefined | CurveCollection CurveChain Create a deep copy of transformed curves. cloneWithExpandedLineStrings(): undefined | CurveCollection CurveChain Create a deep copy with all linestrings expanded to multiple LineSegment3d. closestPoint(spacePoint: Point3d): undefined | CurveLocationDetail CurveChain Return the closest point on the contained curves collectCurvePrimitives(collectorArray?: CurvePrimitive[], smallestPossiblePrimitives: boolean = false, explodeLineStrings: boolean = false): CurvePrimitive[] CurveChain Return an array containing only the curve primitives. cyclicCurvePrimitive(index: number, cyclic: boolean = true): undefined | CurvePrimitive CurveChain Return the [index] curve primitive, optionally using modulo to mapindex to the cyclic indexing. extendRange(range: Range3d, transform?: Transform): void CurveChain invoke curve.extendRange(range, transform) for each child getChild(i: number): undefined | CurvePrimitive CurveChain Return a child by index getPackedStrokes(options?: StrokeOptions): undefined | GrowableXYZArray CurveChain Stroke the chain into a simple xyz array. isAlmostEqual(other: GeometryQuery): boolean CurveChain test for exact structure and nearly identical geometry. maxGap(): number CurveChain return the max gap between adjacent primitives in Path and Loop collections. primitiveIndexAndFractionToCurveLocationDetailPointAndDerivative(index: number, fraction: number, cyclic: boolean = false, result?: CurveLocationDetail): undefined | CurveLocationDetail CurveChain Evaluate an indexed curve at a fraction. range(transform?: Transform, result?: Range3d): Range3d CurveChain return the range of the entire (tree) GeometryQuery reverseChildrenInPlace(): void CurveChain Reverse each child curve (in place) sumLengths(): number CurveChain Return the sum of the lengths of all contained curves. tryAddChild(child: undefined | AnyCurve): boolean CurveChain add a child curve. tryTransformInPlace(transform: Transform): boolean CurveChain Apply transform recursively to children tryTranslateInPlace(dx: number, dy: number = 0.0, dz: number = 0.0): boolean CurveChain try to move the geometry by dx,dy,dz areAlmostEqual(a: undefined | GeometryQuery, b: undefined | GeometryQuery): boolean Static CurveChain apply instance method isAlmostEqual if both are defined. createCurveLocationDetailOnAnyCurvePrimitive(source: undefined | GeometryQuery, fraction: number = 0.5): undefined | CurveLocationDetail Static CurveChain * Find any curve primitive in the source. Properties Name Type Description curveCollectionType Readonly "loop" String name for schema properties isInner boolean tag value that can be set to true for user code to mark inner and outer loops. Inherited properties Name Type Inherited from Description _curves Protected CurvePrimitive[] CurveChain The curve primitives in the chain. children Accessor ReadOnly CurvePrimitive[] CurveChain Return the array of CurvePrimitive geometryCategory Readonly "curveCollection" CurveChain String name for schema properties isAnyRegionType Accessor ReadOnly boolean CurveChain Return true for planar region types:* Loop* ParityRegion* UnionRegion isClosedPath Accessor ReadOnly boolean CurveChain Return true for a single-loop planar region type, i.e. Loop.* This is _not- a test for physical closure of a Path isOpenPath Accessor ReadOnly boolean CurveChain Return true for a Path, i.e. a chain of curves joined head-to-tail Defined in curve/Loop.ts Line 25 Last Updated: 29 November, 2022