ShaderLODTest.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

/// <summary>
/// カメラのZ値によってシェーダを切り替える
/// </summary>
public class ShaderLODTest : MonoBehaviour
{
    [SerializeField]
    private Renderer r;

    [SerializeField]
    private Transform _cameraTransform;

    void Update()
    {
        // シェーダにLOD値を代入
        r.sharedMaterial.shader.maximumLOD = (int) Mathf.Abs(_cameraTransform.localPosition.z);
    }
}