import toolutils

scene_viewer = None
activepane = toolutils.activePane(kwargs)
parent = activepane.pwd()
if activepane.type() != hou.paneTabType.SceneViewer:
    # Use the last selected object
    if parent.childTypeCategory() != hou.objNodeTypeCategory():
        raise hou.Error("This tool cannot be executed in this context")
    selected = [child for child in parent.children() if child.isSelected()]
else:
    scene_viewer = toolutils.sceneViewer()
    selected = scene_viewer.selectObjects(
                prompt = toolutils.selectionPrompt(hou.objNodeTypeCategory()),
                allow_multisel = True,
                allowed_types = ("geo",))

if len(selected) == 0:
    raise hou.Error("Nothing was selected")

for center_obj in selected:
    display = center_obj.displayNode()
    if display is None:
        pivot = hou.Vector3(0, 0, 0)        # Use 0,0,0 by convention
    else:
        geo = display.geometry()
        pivot = geo.boundingBox().center()
    center_obj.parmTuple("p").set(pivot)

if scene_viewer is not None:
    scene_viewer.setCurrentState("pose")