My flower model missed some faces when the camera is in different distance. The camera is far from the model (20000) and the FOV is 5. (We use the perspective camera for a 2D game.) Here are pictures to let you know what happened.
Now when I move the camera closer, the culling faces are different. I changed the FOV or Percent Triangles in Reducing setting, the culling faces will change too. The model has only one LOD level. I also tried to increase model bounds. But they do not help. Does anyone have any ideas about this?