Version: 2019.2
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Matrix4x4.inverse

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public Matrix4x4 inverse;

Description

The inverse of this matrix (Read Only).

Inverted matrix is such that if multiplied by the original would result in identity matrix.

If some matrix transforms vectors in a particular way, then the inverse matrix can transform them back. For example, Transform's worldToLocalMatrix and localToWorldMatrix are inverses of each other.

using UnityEngine;

public class ExampleScript : MonoBehaviour { // Stretch a mesh at an arbitrary angle around the X axis.

// Angle and amount of stretching. float rotAngle; float stretch;

private MeshFilter mf; private Vector3[] origVerts; private Vector3[] newVerts;

void Start() { // Get the Mesh Filter component, save its original vertices // and make a new vertex array for processing. mf = GetComponent< MeshFilter > (); origVerts = mf.mesh.vertices; newVerts = new Vector3[origVerts.Length]; }

void Update() { // Create a rotation matrix from a Quaternion. Quaternion rot = Quaternion.Euler(rotAngle, 0, 0); Matrix4x4 m = Matrix4x4.TRS(Vector3.zero, rot, Vector3.one);

// Get the inverse of the matrix (ie, to undo the rotation). Matrix4x4 inv = m.inverse;

// For each vertex... for (var i = 0; i < origVerts.Length; i++) { // Rotate the vertex and scale it along its new Y axis. Vector3 pt = m.MultiplyPoint3x4(origVerts[i]); pt.y *= stretch;

// Return the vertex to its original rotation (but with the // scaling still applied). newVerts[i] = inv.MultiplyPoint3x4(pt); }

// Copy the transformed vertices back to the mesh. mf.mesh.vertices = newVerts; } }