@chenjm1109
已复现，有时间看一下

I assume this has to do with disposing resources.

I encountered the same problem.
I understand the main reason is that the file with the same path is loaded twice.
The following is my sample code。

    var stlLoader = STLLoader(null);
    var meshGeometry1 = await stlLoader.loadAsync("assets/ClosedArea.stl");
    var meshGeometry2 = await stlLoader.loadAsync("assets/ClosedArea.stl");

When debugging, I found that FileLoader helped me deal with the resource path problem. I understand that the code here is for http to parse the file normally.
https://github.com/wasabia/three_dart/blob/main/lib/three3d/loaders/file_loader.dart#L167-L172

// load assets file TODO
if (url.startsWith("assets")) {
        url = "assets/$url";
      }
      
http.Response response = await http.get(Uri.parse(url ));

This will cause the subsequent loader to be unable to remove the corresponding url
https://github.com/wasabia/three_dart/blob/main/lib/three3d/loaders/file_loader.dart#L191

Then the next time you load, it will think it is still loading and will not be able to return the correct geometry buffer.

I temporarily changed it to the following code and it worked.

      // load assets file TODO
      var httpUrl = url;
      if (httpUrl.startsWith("assets")) {
        httpUrl = "assets/$httpUrl";
      }

      http.Response response = await http.get(Uri.parse(httpUrl));