The viewer applies an OIV.Inventor.Actions.SoGetBoundingBoxAction to the scene graph to get bounding box of the entire scene. The bounding box will only include shapes that are actually traversed. For example the bounding box will not include shapes under an OIV.Inventor.Nodes.SoSwitch with whichChild set to SO_SWITCH_NONE. The action does not consider the visibility of shapes that are traversed. In other words the bounding box will include shapes that are invisible (OIV.Inventor.Nodes.SoDrawStyle), shapes that are clipped (OIV.Inventor.Nodes.SoClipPlane), etc. Use an OIV.Inventor.Nodes.SoBBox node to exclude shapes from the bounding box computation. Bounding boxes are automatically cached at OIV.Inventor.Nodes.SoSeparator nodes, so getting the bounding box is very fast when the scene graph has not been changed.

See all OIV.Inventor.Nodes.SoCamera.ViewAll(OIV.Inventor.Nodes.SoNode, OIV.Inventor.SbViewportRegion, System.Single). This method allows the application to adjust the camera based on a specific sub-graph or path in the scene graph.

Reference