If a SecGraph is created in module or globally in a file it is handled as a filed in the same way as other variables. This means it can be accessed through the attribute editor of this object. In the background the SecGraph is stored as a file and referenced.
For example:
module A(float x, SecGraph sg) extends Box;
protected void init()[
Axiom ==> A(1,new SecGraph(workbench(),new Sphere()));
]