// from the following website                                                                                                 
// https://root.cern.ch/doc/master/classTGeoCtub.html                                                                         

void ctub_orig()
{
   TCanvas *c = new TCanvas("c", "c",0,0,600,600);
   new TGeoManager("ctub", "poza3");
   TGeoMaterial *mat = new TGeoMaterial("Al", 26.98,13,2.7);
   TGeoMedium *med = new TGeoMedium("MED",1,mat);
   TGeoVolume *top = gGeoManager->MakeBox("TOP",med,100,100,100);
   gGeoManager->SetTopVolume(top);
   Double_t theta = 160.*TMath::Pi()/180.;
   Double_t phi   = 30.*TMath::Pi()/180.;
   Double_t nlow[3];
   nlow[0] = TMath::Sin(theta)*TMath::Cos(phi);
   nlow[1] = TMath::Sin(theta)*TMath::Sin(phi);
   nlow[2] = TMath::Cos(theta);
   theta = 20.*TMath::Pi()/180.;
   phi   = 60.*TMath::Pi()/180.;
   Double_t nhi[3];
   nhi[0] = TMath::Sin(theta)*TMath::Cos(phi);
   nhi[1] = TMath::Sin(theta)*TMath::Sin(phi);
   nhi[2] = TMath::Cos(theta);
   TGeoVolume *vol = gGeoManager->MakeCtub("CTUB",med, 20,30,40,-30,250, nlow[0], nlow[1], nlow[2], nhi[0],nhi[1],nhi[2]);
   vol->SetLineWidth(2);
   top->AddNode(vol,1);
   gGeoManager->CloseGeometry();
   gGeoManager->SetNsegments(80);
   top->Draw();
   TView *view = gPad->GetView();
   view->ShowAxis();
}