The internal structure of the tree ( bones )
For the internal structure of this tree there are three functions; animation, positioning of branches and improve performance of model in the software.
Bones are mostly used for animation purposes, like making the tree move, but here they are used to help with three dimension branch positioning.
When c.p's are assigned to bones,the app. becomes more efficient.
The bone structure respects the natural hierarchy of the branches. Image#95
Place the "bones" so that the rotation axis can allow to roll the "child" branch around the "mother" branch. voir Image#94 .
Create an action to position the branch as you wish. Image#96
Manipulate the bones by there roll handels.
More 3D Graphics: 
