API Reference > geometry-core > CartesianGeometry > Matrix3d > createDirectionalScale createDirectionalScale MethodStatic Create a matrix that scales along a specified direction. The scale factor can be negative. A scale of -1.0 (negative one) is a mirror across the plane perpendicular to the vector.The matrix is I−(s−1)UUTwith U being the unit vector in the direction of the input vector.\text{The matrix is } I - (s-1) U U^T \\ \text{with }U\text{ being the unit vector in the direction of the input vector.}The matrix is I−(s−1)UUTwith U being the unit vector in the direction of the input vector. createDirectionalScale(direction: Vector3d, scale: number, result?: Matrix3d): Matrix3d Parameter Type Description direction Vector3d scale number result Matrix3d Returns - Matrix3d Defined in geometry3d/Matrix3d.ts Line 1377 Last Updated: 11 June, 2024