+ Interval y_int;
+ for (int i=0; i < support_l_arr_.size(); i++)
+ {
+ Axis_group_element *common =
+ common_group (support_l_arr_[i], Y_AXIS);
+
+ Real y = support_l_arr_[i]->relative_coordinate (common, Y_AXIS)
+ -relative_coordinate (common,Y_AXIS);
+
+ y_int.unite (y + support_l_arr_[i]->height());
+ }
+
+
+ if (y_int.empty_b())