Version: 2017.2
public Vector2[] uv3 ;


The third texture coordinate set of the mesh, if present.

// Generate planar uv coordinates for all 4 uv sets

using UnityEngine;

public class ExampleClass : MonoBehaviour { void Start() { Mesh mesh = GetComponent<MeshFilter>().mesh; Vector3[] vertices = mesh.vertices; Vector2[] uvs = new Vector2[vertices.Length];

for (int i = 0; i < uvs.Length; i++) uvs[i] = new Vector2(vertices[i].x, vertices[i].z);

mesh.uv2 = uvs; mesh.uv3 = uvs; mesh.uv4 = uvs; } }

Note: Texture coordinates have to be modified or created externally from the mesh. In the script example above the uvs is created as a new array. Then the texture coordinates are assigned to that array. Once these are assigned the array is assigned to the Mesh.