API Reference › core-geometry› Curve › CurveOps › IsPlanar

isPlanar MethodStatic

Check whether or not the curves are planar, and if so, return a localToWorld frame.

isPlanar(curves: MultiLineStringDataVariant | AnyCurve, options?: PlanarColinearOptions): undefined | Transform

@returns localToWorld frame T for coplanar curves, or undefined if they are not coplanar. T satisfies:

  • T.origin is in the plane.
  • T.matrix.columnZ() is the plane unit normal (or its negative).
  • T.matrix.isRigid() returns true.
  • T.inverse() is worldToLocal; apply to input geometry to rotate it into the xy-plane.
Parameter Type Description
curves MultiLineStringDataVariant | AnyCurve input geometry: curves or points.
options PlanarColinearOptions bundle of options.

Returns - undefined | Transform

localToWorld frame T for coplanar curves, or undefined if they are not coplanar. T satisfies:

  • T.origin is in the plane.
  • T.matrix.columnZ() is the plane unit normal (or its negative).
  • T.matrix.isRigid() returns true.
  • T.inverse() is worldToLocal; apply to input geometry to rotate it into the xy-plane.

Defined in

Last Updated: 28 October, 2025