PARENT

Stephan Diehl (diehl@cs.uni-sb.de)
Thu, 22 May 1997 14:52:51 +0200

Sungwoo wrote:
> 2)
> Then, we should name a node explicitly when the node is
> accessed by its child node ? Since the scene graph is
> tree-structured, PARENT seems to cause no problem.
> (I am not sure ...)

Because of DEF/USE the scene graph is directed acyclic graph
(in Script nodes there is also a way to produce a cycle,
this was discussed in www-vrml a few months ago. This
cycle is important to access the node containing a
Script node from within the script).

Here is how you get a DAG:

DEF X SomeNode { }

Transform { children [ USE X
Transfrom { children USE X } ]
}

Now the inner and the outer Transform node are
both parents of X !!!

This doesn't mean that I don't want a PARENT keyword,
I just cannot think of a clean semantics for it.

Any suggestions?
-- Stephan

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EMAIL: diehl@cs.uni-sb.de WWW: http://www.rw.cdl.uni-saarland.de/private/diehl
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