Mesh

Description

A class that allows creating or modifying meshes from scripts.

Meshes contain vertices and multiple triangle arrays. See the Procedural example project for examples of using the mesh interface.

The triangle arrays are simply indices into the vertex arrays; three indices for each triangle.

For every vertex there can be a normal, two texture coordinates, color and tangent. These are optional though and can be removed at will. All vertex information is stored in separate arrays of the same size, so if your mesh has 10 vertices, you would also have 10-size arrays for normals and other attributes.

There are probably 3 things you might want to use the modifyable mesh interface for:

1. Building a mesh from scratch: should always be done in the following order:
a) assign vertices
b) assign triangles.

using UnityEngine;

public class Example : MonoBehaviour
{
    Vector3[] newVertices;
    Vector2[] newUV;
    int[] newTriangles;

    void Start()
    {
        Mesh mesh = new Mesh();
        GetComponent<MeshFilter>().mesh = mesh;
        mesh.vertices = newVertices;
        mesh.uv = newUV;
        mesh.triangles = newTriangles;
    }
}

2. Modifying vertex attributes every frame:
a) get vertices
b) modify them
c) assign them back to the mesh.

using UnityEngine;

public class Example : MonoBehaviour
{
    void Update()
    {
        Mesh mesh = GetComponent<MeshFilter>().mesh;
        Vector3[] vertices = mesh.vertices;
        Vector3[] normals = mesh.normals;

        for (var i = 0; i < vertices.Length; i++)
        {
            vertices[i] += normals[i] * Mathf.Sin(Time.time);
        }

        mesh.vertices = vertices;
    }
}

3. Continously changing the mesh triangles and vertices:
a) call Clear to start fresh
b) assign vertices and other attributes
c) assign triangle indices.

It is important to call Clear before assigning new vertices or triangles. Unity always checks the supplied triangle indices whether they don't reference out of bounds vertices. Calling Clear then assigning vertices then triangles makes sure you never have out of bounds data.

using UnityEngine;

public class ExampleClass : MonoBehaviour
{
    Vector3[] newVertices;
    Vector2[] newUV;
    int[] newTriangles;

    void Start()
    {
        Mesh mesh = GetComponent<MeshFilter>().mesh;

        mesh.Clear();

        // Do some calculations...
        mesh.vertices = newVertices;
        mesh.uv = newUV;
        mesh.triangles = newTriangles;
    }
}

Properties

Constructors

Public Methods

Inherited Members