The Softimage SDK offers many specialized API methods to traverse through relationships of the scene graph. For example:
Parameter.Source (Parameter::GetSource in the C++ API) returns the piece of data attached to (driving) a parameter, such as an FCurve, Shader, Expression or Operator.
The ConstructionHistory allows you to browse the operator stack.
In the object model, you can use the SceneItem.LocalProperties (SceneItem::GetLocalProperties in the C++ API) to get the local versions of shared properties (material, for example).
Geometry.Clusters (Geometry::GetClusters in the C++ API) provides the access to any cluster properties on the object.