API Reference > geometry-core > Curve > DirectSpiral3d > createMXCubicAlongArc createMXCubicAlongArc MethodStatic Create an MX Cubic whose nominal length is close to along the curve. This is y= m*x^3 with m is 1/ (6RL1) 1/(6RL) is the leading term of the sine series. L1 is an along-the-x-axis distance that is slightly LESS THAN the nominal length x is axis position that is slightly LESS than nominal distance along L1, x use the approximation `x = s * ( 1 - s^4/ (40 R R L L)) createMXCubicAlongArc(localToWorld: Transform, nominalL1: number, nominalR1: number, activeInterval?: Segment1d): undefined | DirectSpiral3d Parameter Type Description localToWorld Transform nominalL1 number nominalR1 number activeInterval Segment1d Returns - undefined | DirectSpiral3d Defined in curve/spiral/DirectSpiral3d.ts Line 256 Last Updated: 11 June, 2024