I think the easiest way to do it is to pass "this" to any leaf as a parameter, so that it knows who its parent is, in the same way taht a branch will have a lsit of leaves.

e.g.

Code:

class part
{
  part[] children;
  part parent;
  part(/* other options for creation*/, part _parent)
  {
    /* normal setup */
    parent=_parent;
  }
} 

Than all you have to do in a child, when you need to tell your parent object about some change is do parent.somethingHappened(someOptions); in the child, and the parent will be informed.

What kind of information you need to supply and how it shoudl react is left as an exercise for the reader.

Ok, maybe I have an incomplete understanding of what a scene graph is, but the hand example you've described sounds more complex than a scene graph.  Typically, if you set up a hierarchy of things in a scene, the point of the hierarchy is so that you can move groups of objects easily. So if you create a node that you attach all the parts of a composite object to, you can then move the object by just moving the node. If you move one of the objects directly, it moves relative to its relationship to the node, without affecting the position of the node or any other objects attached to it.

However, if you're just creating a traverseable tree structure, then the method JohnG explains is normal. It's how you traverse the DOM with JavaScript for example.

Im really sorry! I get it now. I was thinking of pass pApplet to each object Not the parent as a this!!

Now I see how they are link!

thank you all so much!


//=======================================================

Quote:


a parent, would be an extends!
But a finger is not a type of hand.

Quote:


how can finger generates an event that calls the parent (Hand) it would have to going world/player/hand witch all must have public methods witch also means other things in the world can call them!

Quote:

If I use "this" I can move from the root in any directshon to any object.

>>>>

I suppose I’m thinking that a scene graph is a data system that could do something like Ragdoll physics.

will my CG lecturer was saying that a scenegraph links all the object dynamically.
If you were (not really) to throw the system box out the window it would that a few seconds but then the screen & keyboard would follow it out the window, because they are linked to the to the system box with the scenegraph!

Code:

/*this is more a sudo code*/
class hand
{
   finger pinker
   hand()
   {
     pinker = new finger();
   }
   move()
   {

   }
}
class finger
{
   finger()
   {
     //...search for fire()
   }

   fire()//thread
   {
     if(found)
     hand.move();//away!!
   }
/* how can finger call hand with out going round the world to get back to the hand*/ 
}
 

big thanks agen ^_^