API Reference > geometry-core > CartesianGeometry > IndexedXYZCollectionPolygonOps > clipConvexPolygonInPlace clipConvexPolygonInPlace MethodStatic Clip a polygon to one side of a plane. Results with 2 or fewer points are ignored. Other than ensuring capacity in the arrays, there are no object allocations during execution of this function. plane is passed as unrolled Point4d (ax,ay,az,aw) point (x,y,z) acts as homogeneous (x,y,z,1) keepPositive === true selects positive altitudes. clipConvexPolygonInPlace(plane: PlaneAltitudeEvaluator, xyz: GrowableXYZArray, work: GrowableXYZArray, keepPositive: boolean = true, tolerance: number = Geometry.smallMetricDistance): number Parameter Type Description plane PlaneAltitudeEvaluator any type that has plane.altitude xyz GrowableXYZArray input points. work GrowableXYZArray work buffer keepPositive boolean tolerance number tolerance for "on plane" decision. Returns - number the number of crossings. If this is larger than 2, the result is "correct" in a parity sense but may have overlapping (hence cancelling) parts. Defined in geometry3d/PolygonOps.ts Line 752 Last Updated: 11 June, 2024