MeshCollider.sharedMesh

Description

The mesh object used for collision detection.

If prior to setting sharedMesh any of the vertices, indices or triangles of the mesh have been changed then the shapes of the MeshCollider will be rebuilt.

using UnityEngine;

public class Example : MonoBehaviour
{
    // Assigns an arbitrary mesh collider to the current transform

    Mesh meshToCollide;

    void Start()
    {
        if (!meshToCollide)
        {
            Debug.LogError("Assign a mesh in the inspector");
            return;
        }
        MeshCollider meshCollider = gameObject.AddComponent<MeshCollider>();
        meshCollider.sharedMesh = meshToCollide;
    }
}