worldBound = child.getWorldBound(); if (worldBound != null)
if (child.getWorldBound() != null) { worldBound = (BoundingVolume)child.getWorldBound().clone();
    public void updateWorldBound() {        boolean foundFirstBound = false;        for (int i = 0, cSize = children.size(); i < cSize ; i++) {            Spatial child = (Spatial) children.get(i);            if (child != null) {                if (foundFirstBound) {                    // merge current world bound with child world bound                    worldBound.mergeLocal(child.getWorldBound());                } else {                    // set world bound to first non-null child world bound                    worldBound = child.getWorldBound();                    if (worldBound != null)                        foundFirstBound = true;                }            }        }    }