double seledg()
{
  ProSelection *sel = NULL;
  int n_sel;
  ProModelitem current_model_item;
  double length,totlength=0.0;
  ProEdge currentedge;

  ProWindowRepaint(PRO_VALUE_UNUSED);  // clear the current window first
  ProSelect("edge", -1, NULL, NULL, NULL, NULL, &sel, &n_sel);

  for (int i=0; i < n_sel; i++){
	ProSelectionModelitemGet(sel[i], & current_model_item);
	ProGeomitemToEdge(& current_model_item,& currentedge);
	ProEdgeLengthEval(currentedge,& length);
	totlength=totlength+length;
  }

  return totlength;
}