Procedurally generated mesh saved twice in scene

Unity Engine
1

I have a component that procedurally generates its mesh. Its GameObject is based on a prefab. The (re)generation looks like that:

DestroyImmediate(mf.sharedMesh);
var mesh = new UnityEngine.Mesh { name = $"{name} (Generated Mesh)" };
updatedMesh.ApplyToUnityMesh(mesh);
mf.sharedMesh = mesh;

Now, when I instantiate the prefab, the generation runs and everything is fine. I can also change parameters and the mesh gets correctly regenerated. However, if I save the scene, there are now two meshes in the .unity file.

--- !u!43 &1699566314
Mesh:
  m_Name: Rubber1 (Generated Mesh)
...
--- !u!43 &1050816235
  m_Name: Rubber1 (Generated Mesh)
...
--- !u!1001 &1084441717
PrefabInstance:
  m_ObjectHideFlags: 0
  serializedVersion: 2
  m_Modification:
    m_TransformParent: {fileID: 241506051}
    m_Modifications:
    - target: {fileID: 4392546155774236836, guid: 073cf4ebd8b550b4699ac09545ec5673,
        type: 3}
      propertyPath: m_Mesh
      value:
      objectReference: {fileID: 1699566314}

So one of the meshes is referenced in the prefab modifications, and the other looks like an orphan.

Does anyone have an idea what the cause of this might be?

2

Hi @phreezie . If you think this is a bug, please file a bug report and attach a minimal repro project. Just follow the steps on this page: Unity QA: Building quality with passion. Thanks.

3

Well, from my understanding, Unity keeps the original values of overridden props in the game object in order to be able to easily restore them. So I don’t think it’s a bug, it’s just that mesh data is somewhat large, and I wondered if there’s a way to clean this.