void RecursiveInvisible(TGeoVolume *vol);
void RecursiveTransparency(TGeoVolume *vol, Int_t transp);

void geomD0(Int_t allVisible = 0)
{
   TGeoManager::Import("http://root.cern/files/d0.root");
   gGeoManager->DefaultColors();
   gGeoManager->SetMaxVisNodes(40000);
   // gGeoManager->SetVisLevel(4);
   if (!allVisible) {
      RecursiveInvisible(gGeoManager->GetVolume("D0-"));
      RecursiveInvisible(gGeoManager->GetVolume("D0+"));
      RecursiveInvisible(gGeoManager->GetVolume("D0WZ"));
      RecursiveInvisible(gGeoManager->GetVolume("D0WL"));
      RecursiveTransparency(gGeoManager->GetVolume("MUON"), 90);
   }

   gGeoManager->GetVolume("D0")->Draw("ogl");
}

void RecursiveInvisible(TGeoVolume *vol)
{
   vol->InvisibleAll();
   Int_t nd = vol->GetNdaughters();
   for (Int_t i = 0; i < nd; i++) {
      RecursiveInvisible(vol->GetNode(i)->GetVolume());
   }
}

void RecursiveTransparency(TGeoVolume *vol, Int_t transp)
{
   vol->SetTransparency(transp);
   Int_t nd = vol->GetNdaughters();
   for (Int_t i = 0; i < nd; i++) {
      RecursiveTransparency(vol->GetNode(i)->GetVolume(), transp);
   }
}