Finding the bounds and hit detection

If you want to find the bounds on a nested group or graphic within the group, you have to use an iterator to locate the graphic or nested group that has been selected. To do this, call the TGraphicGroup3D::CreateIterator function that returns a TGraphicIterator3D instance. TGraphicIterator3D is an abstract base class, and by default CreateIterator creates a shallow iterator that iterates one level of the group.