API Reference › core-geometry › Curve › JointOptions

JointOptions Class

Control parameters for joint construction, used in offset construction methods such as RegionOps.constructPolygonWireXYOffset and Region.Ops.constructCurveXYOffset.

  • Define a "joint" as the common point between adjacent segments of the input curve.
  • Define the "turn angle" at a joint to be the angle in [0,pi] between the first derivatives (tangents) of the segments at the joint.
  • When creating offsets, if an offset needs to do an "outside" turn, the first applicable construction is applied:
  • If the turn angle is larger than options.minArcDegrees, a circular arc is constructed to offset the joint.
  • If the turn angle is less than or equal to options.maxChamferTurnDegrees, extend curves along tangent to single intersection point (to create a sharp corner).
  • If the turn angle is larger than options.maxChamferDegrees, the joint is offset with a line string whose edges:
    • lie outside the arc that would have been created by the first construction
    • have uniform turn angle less than options.maxChamferDegrees
    • touch the arc at their midpoint (except first and last edge).

Methods

Name Description
constructor(leftOffsetDistance: number, minArcDegrees: number = 180, maxChamferDegrees: number = 90, preserveEllipticalArcs: boolean = false, allowSharpestCorners: boolean = false): JointOptions Construct JointOptions.  
clone(): JointOptions Return a deep clone.  
needArc(theta: Angle): boolean Return true if the options indicate this amount of turn should be handled with an arc.  
numChamferPoints(theta: Angle): number Return the number of corners needed to chamfer the given turn angle.  
setFrom(other: JointOptions): void Copy values of input options  
create(leftOffsetDistanceOrOptions: number | JointOptions): JointOptions Static Parse a number or JointOptions up to JointOptions:  

Properties

Name Type Description
allowSharpestCorners boolean Whether to remove the internal turn angle upper bound for sharp corner construction.  
leftOffsetDistance number Offset distance, positive to left of base curve.  
maxChamferTurnDegrees number Largest turn angle at which to construct a sharp corner, or largest turn angle in a multi-segment chamfer.  
minArcDegrees number Smallest arc to construct.  
preserveEllipticalArcs boolean Whether to offset elliptical arcs as elliptical arcs (true) or as B-spline curves (false, default).  

Defined in

Last Updated: 20 April, 2024