Class diagram

http://www.kissthepax.org/iAnimTree.jpg

Example tree

http://www.kissthepax.org/ExampleAnimTree.jpg

Example as XML

<overwriteNode name="Gesture">
  <blendNode name="Motion" priority="1">
    <leafNode name="Walk">
      <animation file="PersonWalk" />
    </leafNode>
    <leafNode name="Run">
      <animation file="PersonRun" />
    </leafNode>
  </blendNode>
  <leafNode name="ArmWave" priority="2">
    <animation file="PersonWaveHand" />
  </leafNode>
</overwriteNode>