API Reference > geometry-core > Bspline > BSplineSurface3dQuery > fractionToRigidFrame fractionToRigidFrame Method Evaluate a rigid frame at fractional parameter u,v origin is at the surface point x column is a unit vector in the direction of the u derivative y column is a unit vector in the direction of the v derivative z direction is the surface normal fractionToRigidFrame(uFraction: number, vFraction: number): Transform | undefined Parameter Type Description uFraction number vFraction number Returns - Transform | undefined Defined in core/geometry/src/bspline/BSplineSurface.ts Line 90 Last Updated: 13 June, 2024