Double_t kDis;
Int_t cLevel = 0;

void checkOverlap(Double_t dis = 0.1)
{
  kDis = dis;
  TFile *f = new TFile("geom.root");

  TGeoManager *geo = (TGeoManager*)f->Get("PHENIX");

  TGeoVolume *volCheck = geo->GetVolume("HALL");
  geo->SetTopVolume(volCheck);
  //gGeoManager->CloseGeometry();

  static const Int_t kNLevel = 1;
  TGeoVolume *volOnLevel[kNLevel];
  TGeoNode *nodeOnLevel[kNLevel];
  Int_t    countOnLevel[kNLevel];

  Int_t    iLevel = 0;
  volOnLevel[0] = volCheck;

  cLevel = 0;
  //LoopDaughters(volCheck);
  //while (iLevel < kNLevel) {
  //for (countOnLevel[iLevel] = 0; countOnLevel[iLevel] < volOnLevel[iLevel]->GetNdaughters(); countOnLevel[iLevel]++) {
    //std::cout << "level " << iLevel << "  " << volOnLevel[iLevel]->GetNode(countOnLevel[iLevel])->GetName() << std::endl;
    //nodeOnLevel[]    

  //TGeoNode *nodeSIEN = fVolHALL->GetNode("SIEN_1");
  //nodeSIEN->GetVolume()->Draw();
  //TGeoVolume *volSIEN = nodeSIEN->GetVolume();

  //volCheck->CheckOverlaps(kDis);
  geo->CheckOverlaps(kDis);
  geo->PrintOverlaps();


}

void LoopDaughters(TGeoVolume *vol)
{
  for (Int_t i = 0; i < vol->GetNdaughters(); i++) {
    cLevel++;
    TGeoNode *nodeChild = vol->GetNode(i);
    for (Int_t j = 0; j < cLevel; j++) std::cout << "  ";
    std::cout << nodeChild->GetName() << std::endl;
    TGeoVolume *volChild = nodeChild->GetVolume();
    volChild->CheckOverlaps(kDis);
    LoopDaughters(volChild);
  }
  cLevel--;
}