A path represents a scene graph or subgraph. It contains a list of nodes forming a chain from some root to some descendant. Each node in the chain is a child of the previous node. Paths are used to refer to some object in a scene graph precisely and unambiguously, even if there are many instances of the object. Therefore, paths are returned by both the OIV.Inventor.Actions.SoRayPickAction and OIV.Inventor.Actions.SoSearchAction.

When an action is applied to a path, only the nodes in the subgraph defined by the path are traversed. These include: the nodes in the path chain, all nodes (if any) below the last node in the path, and all nodes whose effects are inherited by any of these nodes.

OIV.Inventor.SoPath attempts to maintain consistency of paths even when the structure of the scene graph changes. For example, removing a child from its parent when both are in a path chain cuts the path chain at that point, leaving the top part intact. Removing the node to the left of a node in a path adjusts the index for that node. Replacing a child of a node when both the parent and the child are in the chain replaces the child in the chain with the new child, truncating the path below the new child.

Hidden children

Note that only public children of nodes are accessible from an OIV.Inventor.SoPath. Nodes like node kits limit access to their children and these "hidden children" will not be visible using the OIV.Inventor.SoPath methods.

For example, if your application does picking and gets a path from OIV.Inventor.Actions.SoRayPickAction, the actual last node in the path (tail) will normally be a shape node. But if that shape is part of a node kit, then the GetTail() method will return the node kit, not the shape node. To access all hidden children in the path, simply cast the path object to OIV.Inventor.SoFullPath before calling get methods. To access hidden node kit children (but not all children) in the path, cast the path object to OIV.Inventor.SoNodeKitPath before calling get methods. Node References:

An OIV.Inventor.SoPath object maintains a reference to every node in the path. These nodes will not be garbage collected as long as the OIV.Inventor.SoPath exists. Actions that return an OIV.Inventor.SoPath, for example OIV.Inventor.Actions.SoSearchAction and OIV.Inventor.Actions.SoRayPickAction, maintain a reference to the returned path (or paths). As long as the action exists and is not reset, the nodes referenced by the path cannot be garbage collected. See the OIV.Inventor.Actions.SoAction method clearApplyResult().

FILE FORMAT/DEFAULT

OIV.Inventor.SoPath {

[head node]
[number of remaining indices]
[index]
&...
[index]

}

Note that the indices in a written path are adjusted based on the nodes that are actually written to a file. Since nodes in the graph that have no effect on the path (such as some separator nodes) are not written, the siblings of such nodes must undergo index adjustment when written. The actual nodes in the graph remain unchanged.

OIV.Inventor.SoPath is not able to write "per instance" information to a file for instancing nodes like OIV.Inventor.Nodes.SoMultipleInstance and OIV.Inventor.Nodes.SoMultipleCopy. The saved path will reference the whole set of instances under OIV.Inventor.Nodes.SoMultipleInstance or SoMulitpleCopy node.

Reference