title: How can I access the mesh data of a MeshInstance?
body: <p>I'm trying, without success, to access the data of a mesh from a MeshInstance node.</p>
  
  <p>I've imported a 3d object, opened it as "New Inherited", turned it as "Unique" and saved it as <strong><em>foo.mesh</em></strong>. Then, on a new scene, I did create a MeshInstance and loaded the foo.mesh as its Mesh.</p>
  
  <p>The Script is attached to the very MeshInstance, kinda like follows:</p>
  
  <pre><code>extends MeshInstance
  
  func _ready():
      var themesh = Mesh
      var mdt = MeshDataTool.new()
      if mdt.create_from_surface(themesh, 0):
          print("Ok!!")
          print(mdt.get_vertex_count()) # get_vertex_count() returns 0
      else:
          print("Failed...")
  </code></pre>