protected void setLightListRefresh() {
        refreshFlags |= RF_LIGHTLIST;
        // Make sure next updateGeometricState() visits this branch
        // to update lights.
        Spatial p = parent;
        while (p != null) {
            if ((p.refreshFlags & RF_CHILD_LIGHTLIST) != 0) {
                // The parent already has this flag,
                // so must all ancestors.
                return;
            }
            p.refreshFlags |= RF_CHILD_LIGHTLIST;
            p = p.parent;
        }
    }
Indicate that the transform of this spatial has changed and that
a refresh is required.
jme3-core/src/main/java/com/jme3/scene/Spatial.java