使用的是GLTFUtility https://github.com/Siccity/GLTFUtility.git
gltf样品库 https://github.com/KhronosGroup/glTF-Sample-Models.git
我的测试模型 https://www.xuefei.net.cn/unitywebgl/WaterBottle.glb
我的webgl测试地址 https://www.xuefei.net.cn/unitywebgl/index.html
主要代码

using System.Collections;
using UnityEngine;
using Siccity.GLTFUtility;
using UnityEngine.UI;
using UnityEngine.Networking;

public class GLTFTest : MonoBehaviour
{
    public Button button;
    public GameObject loadGo = null;

    // Start is called before the first frame update
    void Start()
    {
        button.onClick.AddListener(delegate
        {
            StartCoroutine(LoadGo());
        });
    }

    private IEnumerator LoadGo()
    {
        if (loadGo != null)
        {
            DestroyImmediate(loadGo);
            Resources.UnloadUnusedAssets();
        }
        var request = UnityWebRequest.Get("https://www.xuefei.net.cn/unitywebgl/WaterBottle.glb");
        yield return request.SendWebRequest();
        if (request.result != UnityWebRequest.Result.Success)
        {
            Debug.LogError(request.error);
        }
        else
        {
            Debug.Log(request.downloadHandler.text);
            loadGo = Importer.LoadFromBytes(request.downloadHandler.data);
        }
    }
}

效果图