def addTransform(self): """Create and add a transform node with a display node to the mrmlScene. Returns the transform node and its display node """ transformNode = slicer.mrmlScene.AddNode(slicer.vtkMRMLTransformNode()) transformDisplayNode = slicer.mrmlScene.AddNode(slicer.vtkMRMLTransformDisplayNode()) transformNode.SetAndObserveDisplayNodeID(transformDisplayNode.GetID()) return transformNode, transformDisplayNode