UML Diagram:
  https://docs.google.com/a/g.ucla.edu/drawings/d/1VqDGhvkOAENNGSycoFwKZj1IVB1zyKaCH_UZjw4bISE/edit

OpenAlea Docuemntation:
  http://openalea.gforge.inria.fr/doc/openalea/doc/_build/html/index.html