C++ TGeoVolume::SetVisibility方法代码示例

void visibility_all_volumes(Bool_t vis_state)
{
   TGeoVolume *v;
   TIter it(gGeoManager->GetListOfVolumes());
   while ((v = (TGeoVolume*) it()) != 0)
   {
      v->SetVisibility(vis_state);
   }
   full_update();
}

 virtual TGeoVolume* MakeCopyVolume(TGeoShape *newshape) {
   // make a copy of this volume. build a volume with same name, shape and medium
   TGeoVolume *vol = _copyVol(newshape);
   vol->SetVisibility(IsVisible());
   vol->SetLineColor(GetLineColor());
   vol->SetLineStyle(GetLineStyle());
   vol->SetLineWidth(GetLineWidth());
   vol->SetFillColor(GetFillColor());
   vol->SetFillStyle(GetFillStyle());
   vol->SetField(fField);
   if (fFinder)
     vol->SetFinder(fFinder);
   CloneNodesAndConnect(vol);
   ((TObject*) vol)->SetBit(kVolumeClone);
   return vol;
 }

void visibility_volume_by_material(const char* material_re, Bool_t vis_state)
{
   TPMERegexp re(material_re, "o");
   TGeoMaterial *m;
   TIter it(gGeoManager->GetListOfMaterials());
   while ((m = (TGeoMaterial*) it()) != 0)
   {
      if (re.Match(m->GetName()))
      {
         TGeoVolume *v;
         TIter it2(gGeoManager->GetListOfVolumes());
         while ((v = (TGeoVolume*) it2()) != 0)
         {
            if (v->GetMaterial() == m)
            {
               v->SetVisibility(vis_state);
            }
         }
      }
   }
   full_update();
}

void rootgeom()
{
//Definition of a simple geometry (the 4 ROOT characters)
//Author: Andrei Gheata
   
   // gStyle->SetCanvasPreferGL(true);
   gSystem->Load("libGeom");
   TGeoManager *geom = new TGeoManager("simple1", "Simple geometry");
   
   //--- define some materials
   TGeoMaterial *matVacuum = new TGeoMaterial("Vacuum", 0,0,0);
   TGeoMaterial *matAl = new TGeoMaterial("Al", 26.98,13,2.7);
//   //--- define some media
   TGeoMedium *Vacuum = new TGeoMedium("Vacuum",1, matVacuum);
   TGeoMedium *Al = new TGeoMedium("Root Material",2, matAl);

   //--- define the transformations
   TGeoTranslation *tr1 = new TGeoTranslation(20., 0, 0.);
   TGeoTranslation *tr2 = new TGeoTranslation(10., 0., 0.);
   TGeoTranslation *tr3 = new TGeoTranslation(10., 20., 0.);
   TGeoTranslation *tr4 = new TGeoTranslation(5., 10., 0.);
   TGeoTranslation *tr5 = new TGeoTranslation(20., 0., 0.);
   TGeoTranslation *tr6 = new TGeoTranslation(-5., 0., 0.);
   TGeoTranslation *tr7 = new TGeoTranslation(7.5, 7.5, 0.);
   TGeoRotation   *rot1 = new TGeoRotation("rot1", 90., 0., 90., 270., 0., 0.);
   TGeoCombiTrans *combi1 = new TGeoCombiTrans(7.5, -7.5, 0., rot1);
   TGeoTranslation *tr8 = new TGeoTranslation(7.5, -5., 0.);
   TGeoTranslation *tr9 = new TGeoTranslation(7.5, 20., 0.);
   TGeoTranslation *tr10 = new TGeoTranslation(85., 0., 0.);
   TGeoTranslation *tr11 = new TGeoTranslation(35., 0., 0.);
   TGeoTranslation *tr12 = new TGeoTranslation(-15., 0., 0.);
   TGeoTranslation *tr13 = new TGeoTranslation(-65., 0., 0.);
   
   TGeoTranslation  *tr14 = new TGeoTranslation(0,0,-100);
   TGeoCombiTrans *combi2 = new TGeoCombiTrans(0,0,100, 
                                   new TGeoRotation("rot2",90,180,90,90,180,0));
   TGeoCombiTrans *combi3 = new TGeoCombiTrans(100,0,0, 
                                   new TGeoRotation("rot3",90,270,0,0,90,180));
   TGeoCombiTrans *combi4 = new TGeoCombiTrans(-100,0,0, 
                                   new TGeoRotation("rot4",90,90,0,0,90,0));
   TGeoCombiTrans *combi5 = new TGeoCombiTrans(0,100,0, 
                                   new TGeoRotation("rot5",0,0,90,180,90,270));
   TGeoCombiTrans *combi6 = new TGeoCombiTrans(0,-100,0, 
                                   new TGeoRotation("rot6",180,0,90,180,90,90));
   
   //--- make the top container volume
   Double_t worldx = 110.;
   Double_t worldy = 50.;
   Double_t worldz = 5.;
   TGeoVolume *top = geom->MakeBox("TOP", Vacuum, 270., 270., 120.);
   geom->SetTopVolume(top);
   TGeoVolume *replica = geom->MakeBox("REPLICA", Vacuum,120,120,120);
   replica->SetVisibility(kFALSE);
   TGeoVolume *rootbox = geom->MakeBox("ROOT", Vacuum, 110., 50., 5.);
   rootbox->SetVisibility(kFALSE);
   
   //--- make letter 'R'
   TGeoVolume *R = geom->MakeBox("R", Vacuum, 25., 25., 5.);
   R->SetVisibility(kFALSE);
   TGeoVolume *bar1 = geom->MakeBox("bar1", Al, 5., 25, 5.);
   bar1->SetLineColor(kRed);
   R->AddNode(bar1, 1, tr1);
   TGeoVolume *bar2 = geom->MakeBox("bar2", Al, 5., 5., 5.);
   bar2->SetLineColor(kRed);
   R->AddNode(bar2, 1, tr2);
   R->AddNode(bar2, 2, tr3);
   TGeoVolume *tub1 = geom->MakeTubs("tub1", Al, 5., 15., 5., 90., 270.);
   tub1->SetLineColor(kRed);
   R->AddNode(tub1, 1, tr4);
   TGeoVolume *bar3 = geom->MakeArb8("bar3", Al, 5.);
   bar3->SetLineColor(kRed);
   TGeoArb8 *arb = (TGeoArb8*)bar3->GetShape();
   arb->SetVertex(0, 15., -5.);
   arb->SetVertex(1, 0., -25.);
   arb->SetVertex(2, -10., -25.);
   arb->SetVertex(3, 5., -5.);
   arb->SetVertex(4, 15., -5.);
   arb->SetVertex(5, 0., -25.);
   arb->SetVertex(6, -10., -25.);
   arb->SetVertex(7, 5., -5.);
   R->AddNode(bar3, 1, gGeoIdentity);
   
   //--- make letter 'O'
   TGeoVolume *O = geom->MakeBox("O", Vacuum, 25., 25., 5.);
   O->SetVisibility(kFALSE);
   TGeoVolume *bar4 = geom->MakeBox("bar4", Al, 5., 7.5, 5.);
   bar4->SetLineColor(kYellow);
   O->AddNode(bar4, 1, tr5);
   O->AddNode(bar4, 2, tr6);
   TGeoVolume *tub2 = geom->MakeTubs("tub1", Al, 7.5, 17.5, 5., 0., 180.);
   tub2->SetLineColor(kYellow);
   O->AddNode(tub2, 1, tr7);
   O->AddNode(tub2, 2, combi1);
   
   //--- make letter 'T'
   TGeoVolume *T = geom->MakeBox("T", Vacuum, 25., 25., 5.);
   T->SetVisibility(kFALSE);
   TGeoVolume *bar5 = geom->MakeBox("bar5", Al, 5., 20., 5.);
   bar5->SetLineColor(kBlue);
   T->AddNode(bar5, 1, tr8);
//.........这里部分代码省略.........

//.........这里部分代码省略.........
  Bbul->SetLineColor(17);
  Bbul->SetFillColor(17);

  // drawing arms
  top->AddNodeOverlap(S, 1, new TGeoCombiTrans(3, 73, 30, new TGeoRotation("R2", 0, -30, 0)));
  top->AddNodeOverlap(S, 1, new TGeoCombiTrans(3, -73, 30, new TGeoRotation("R2", 0, 210, 0)));
  top->AddNodeOverlap(S_1, 1, new TGeoCombiTrans(3, -73, 27, new TGeoRotation("R2", 0, 0, 0)));
  top->AddNodeOverlap(S_1, 1, new TGeoCombiTrans(3, 73, 27, new TGeoRotation("R2", 0, 0, 0)));
  top->AddNodeOverlap(Pal, 1, new TGeoCombiTrans(3, -73, -5, new TGeoRotation("R2", 0, 0, 0)));
  top->AddNodeOverlap(Pal, 1, new TGeoCombiTrans(3, 73, -5, new TGeoRotation("R2", 0, 0, 0)));
  top->AddNodeOverlap(Fal, 1, new TGeoCombiTrans(3, -73, -60, new TGeoRotation("R2", 0, 0, 0)));
  top->AddNodeOverlap(Fal, 1, new TGeoCombiTrans(3, 73, -60, new TGeoRotation("R2", 0, 0, 0)));
  top->AddNodeOverlap(Bbul, 1, new TGeoCombiTrans(3, -97, -72, new TGeoRotation("R2", 0, -90, 0)));
  top->AddNodeOverlap(Bbul, 1, new TGeoCombiTrans(3, -97, -48, new TGeoRotation("R2", 0, -90, 0)));
  top->AddNodeOverlap(Bbul, 1, new TGeoCombiTrans(3, 97, -72, new TGeoRotation("R2", 0, 90, 0)));
  top->AddNodeOverlap(Bbul, 1, new TGeoCombiTrans(3, 97, -48, new TGeoRotation("R2", 0, 90, 0)));

  // hands
  TGeoVolume *Son_d = Robot->MakeBox("Son_d", Iron, 15, 15, 7);
  Son_d->SetLineColor(4);
  Son_d->SetFillColor(4);
  TGeoVolume *Son_g = Robot->MakeBox("Son_g", Iron, 4, 10, 4);
  Son_g->SetLineColor(4);
  Son_g->SetFillColor(4);
  TGeoVolume *Son_g1 = Robot->MakeBox("Son_g1", Iron, 6, 6, 6);
  Son_g1->SetLineColor(4);
  Son_g1->SetFillColor(4);
  TGeoVolume *Son_g2 = Robot->MakeBox("Son_g2", Iron, 8, 3, 3);
  Son_g2->SetLineColor(4);
  Son_g2->SetFillColor(4);
  TGeoVolume *Last_b = Robot->MakeCone("Last_b", Iron, 10, 0, 0, 0, 4);
  Last_b->SetLineColor(17);
  Last_b->SetFillColor(17);
  TGeoVolume *Last = Robot->MakeSphere("Last", Iron, 0, 3, 0, 180, 0, 360);
  Last->SetLineColor(2);
  Last->SetFillColor(2);

  // drawing hands
  top->AddNodeOverlap(Son_d, 1, new TGeoCombiTrans(3, -80, -105, new TGeoRotation("R2", 0, 90, 0)));
  for (int i = 0; i < 4; i++) {
    top->AddNodeOverlap(Son_g, 1, new TGeoCombiTrans(-6 + 6 * i, -72, -118, new TGeoRotation("R2", 0, -10, 0)));
  }
  for (int i = 0; i < 4; i++) {
    top->AddNodeOverlap(Son_g, 1, new TGeoCombiTrans(-6 + 6 * i, -67, -113, new TGeoRotation("R2", 0, 110, 0)));
  }
  top->AddNodeOverlap(Son_g1, 1, new TGeoCombiTrans(-5, -70, -98, new TGeoRotation("R2", 0, 0, 0)));
  top->AddNodeOverlap(Son_g2, 1, new TGeoCombiTrans(-5, -65, -102, new TGeoRotation("R2", 0, 60, 0)));
  top->AddNodeOverlap(Son_d, 1, new TGeoCombiTrans(3, 80, -105, new TGeoRotation("R2", 0, 90, 0)));
  for (int i = 0; i < 4; i++) {
    top->AddNodeOverlap(Son_g, 1, new TGeoCombiTrans(-6 + 6 * i, 72, -118, new TGeoRotation("R2", 0, 10, 0)));
  }
  for (int i = 0; i < 4; i++) {
    top->AddNodeOverlap(Son_g, 1, new TGeoCombiTrans(-6 + 6 * i, 67, -113, new TGeoRotation("R2", 0, 70, 0)));
  }
  top->AddNodeOverlap(Son_g1, 1, new TGeoCombiTrans(-5, 70, -98, new TGeoRotation("R2", 0, 0, 0)));
  top->AddNodeOverlap(Son_g2, 1, new TGeoCombiTrans(-5, 65, -102, new TGeoRotation("R2", 0, 60, 0)));
  top->AddNodeOverlap(Last_b, 1, new TGeoCombiTrans(3, -88, -103, new TGeoRotation("R2", 0, 180, 0)));
  top->AddNodeOverlap(Last_b, 1, new TGeoCombiTrans(12, -88, -103, new TGeoRotation("R2", 0, 180, 0)));
  top->AddNodeOverlap(Last_b, 1, new TGeoCombiTrans(-7, -88, -103, new TGeoRotation("R2", 0, 180, 0)));
  top->AddNodeOverlap(Last_b, 1, new TGeoCombiTrans(3, 88, -103, new TGeoRotation("R2", 0, 180, 0)));
  top->AddNodeOverlap(Last_b, 1, new TGeoCombiTrans(12, 88, -103, new TGeoRotation("R2", 0, 180, 0)));
  top->AddNodeOverlap(Last_b, 1, new TGeoCombiTrans(-7, 88, -103, new TGeoRotation("R2", 0, 180, 0)));
  top->AddNodeOverlap(Last, 1, new TGeoCombiTrans(3, -88, -112, new TGeoRotation("R2", 0, 180, 0)));
  top->AddNodeOverlap(Last, 1, new TGeoCombiTrans(12, -88, -112, new TGeoRotation("R2", 0, 180, 0)));
  top->AddNodeOverlap(Last, 1, new TGeoCombiTrans(-7, -88, -112, new TGeoRotation("R2", 0, 180, 0)));
  top->AddNodeOverlap(Last, 1, new TGeoCombiTrans(3, 88, -112, new TGeoRotation("R2", 0, 180, 0)));
  top->AddNodeOverlap(Last, 1, new TGeoCombiTrans(12, 88, -112, new TGeoRotation("R2", 0, 180, 0)));
  top->AddNodeOverlap(Last, 1, new TGeoCombiTrans(-7, 88, -112, new TGeoRotation("R2", 0, 180, 0)));

  for (int i = 1; i < 20; i += 1) {
    if (i < 7) {
      TGeoVolume *Effect =
          Robot->MakeCons("Effect", Iron, 3, 20 / sin(i), 21 / sin(i), 20 / sin(i), 21 / sin(i), 0, 70);
      Effect->SetLineColor(9);
      Effect->SetFillColor(9);
      top->AddNodeOverlap(Effect, 1, new TGeoTranslation(3, 0, -280));
    }
    if (6 < i && i < 10) {
      TGeoVolume *Effect =
          Robot->MakeCons("Effect", Iron, 5, 20 / sin(i), 21 / sin(i), 20 / sin(i), 21 / sin(i), 50, 120);
      Effect->SetLineColor(38);
      Effect->SetFillColor(38);
      top->AddNodeOverlap(Effect, 1, new TGeoTranslation(3, 0, -280));
    }
    if (9 < i && i < 20) {
      TGeoVolume *Effect =
          Robot->MakeCons("Effect", Iron, 4, 20 / sin(i), 21 / sin(i), 20 / sin(i), 21 / sin(i), 200, 330);
      Effect->SetLineColor(33);
      Effect->SetFillColor(33);
      top->AddNodeOverlap(Effect, 1, new TGeoTranslation(3, 0, -280));
    }
  }

  // close geometry
  top->SetVisibility(0);
  Robot->CloseGeometry();

  // in GL viewer
  top->Draw("ogl");
}

drawFGT(TString volName="")
{
  gSystem->Load("libGeom");
  gSystem->Load("libGdml");

  TGeoManager::Import("fgt.gdml");
  gGeoManager->DefaultColors();

  bool allSolid=true;
  
  char topVol[] ="volWorld";
  //char topVol[] ="volDetEnclosure";
  //char topVol[] ="volDetector";

  //char topVol[] ="volMuIDDownstream";
  //char topVol[] ="volMuIDBarrel";
  //char topVol[] ="volRPCMod";
  //char topVol[] ="volRPCTray_End";

  //char topVol[] ="volECALDownstream";
  //char topVol[] ="volECALUpstream";
  //char topVol[] ="volBarrelECAL";
  //char topVol[] ="volSBPlane";

  //char topVol[] ="volSTT";
  //char topVol[] ="volSTPlaneTarget";
  //char topVol[] ="volSTPlaneRadiator";
  //char topVol[] ="volTargetPlaneArgon";


  gGeoManager->GetVolume("volDetEnclosure")->SetLineColor(kGray);
  gGeoManager->GetVolume("volDetEnclosure")->SetVisibility(1);
  gGeoManager->GetVolume("volDetEnclosure")->SetTransparency(20);

  gGeoManager->GetVolume("volDirtLayer")->SetTransparency(20);

  gGeoManager->GetVolume("volServiceBuilding")->SetLineColor(kGray);
  gGeoManager->GetVolume("volServiceBuilding")->SetVisibility(1);
  gGeoManager->GetVolume("volServiceBuilding")->SetTransparency(20);


  gGeoManager->GetVolume("volSky")->SetLineColor(kWhite);
  gGeoManager->GetVolume("volSky")->SetVisibility(1);
  gGeoManager->GetVolume("volSky")->SetTransparency(20);


  gGeoManager->GetVolume("volMagnet")->SetLineColor(kGreen-1);
  gGeoManager->GetVolume("volMagnet")->SetVisibility(1);
  if(!allSolid) gGeoManager->GetVolume("volMagnet")->SetTransparency(10);


  gGeoManager->GetVolume("volECALBarrelMod")->SetLineColor(kRed);
  gGeoManager->GetVolume("volECALBarrelMod")->SetVisibility(1);
  if(!allSolid) gGeoManager->GetVolume("volECALBarrelMod")->SetTransparency(75);
  
  gGeoManager->GetVolume("volSBPlane")->SetLineColor(kRed-3);
  gGeoManager->GetVolume("volSBPlane")->SetVisibility(1);
  if(!allSolid) gGeoManager->GetVolume("volSBPlane")->SetTransparency(80);
  /*
  gGeoManager->GetVolume("volECALUpstream")->SetLineColor(kYellow-3);
  gGeoManager->GetVolume("volECALUpstream")->SetVisibility(1);
  gGeoManager->GetVolume("volECALUpstream")->SetTransparency(20);
  gGeoManager->GetVolume("volECALDownstream")->SetLineColor(kYellow-3);
  gGeoManager->GetVolume("volECALDownstream")->SetVisibility(1);
  gGeoManager->GetVolume("volECALDownstream")->SetTransparency(20);
  */
  
  TObjArray* va = gGeoManager->GetListOfVolumes();
  int nv = va->GetEntries();
  for (int i=0; i<nv; ++i) {
    TGeoVolume* v = (TGeoVolume*)va->At(i);
    std::string m(v->GetMaterial()->GetName());
    //cout << v->GetMaterial()->GetName() << endl;
    int lc, vi, tr, vd;
    if           (m == "Scintillator")             { 
      lc = kGreen-7 ; vi = 1; tr = 0; vd = 1; 
      v->SetLineColor(lc);
      v->SetVisibility(vi);
      v->VisibleDaughters(vd);
      v->SetTransparency(tr);
    }
    //else {
    //  continue;
      //std::cout << "'" << m << "' has no defaults" << std::endl;
      //lc = kOrange; vi = 0; tr = 50; vd = 1; 
    //}

  }
  

 //gGeoManager->GetTopNode();
 gGeoManager->CheckOverlaps(1e-5,"d");
 gGeoManager->PrintOverlaps();
 //gGeoManager->FindVolumeFast(topVol)->CheckOverlaps(1e-5,"d");
 //gGeoManager->FindVolumeFast(topVol)->GetNode(0)->PrintOverlaps();
 gGeoManager->SetMaxVisNodes(70000);


 gGeoManager->FindVolumeFast(topVol)->Draw("ogl");

//.........这里部分代码省略.........

//.........这里部分代码省略.........
   top->AddNodeOverlap(mBlock,1,new TGeoCombiTrans(0,110,550, new TGeoRotation("r1",0,45,0)));



   sprintf(nBlocks,"ab%d",N++);
   mBlock = geom->MakeBox(nBlocks, Iron, 110,10,2);
   mBlock->SetLineColor(42);   
   top->AddNodeOverlap(mBlock,1,new TGeoCombiTrans(335,0,550, new TGeoRotation("r1",90,-45,0)));



   sprintf(nBlocks,"ab%d",N++);
   mBlock = geom->MakeBox(nBlocks, Iron, 110,10,2);
   mBlock->SetLineColor(42);   
   top->AddNodeOverlap(mBlock,1,new TGeoCombiTrans(-335,0,550, new TGeoRotation("r1",90,45,0)));



////////////////////////////////add box





k=0; i=0;

while (i<5){   
while(k<6){
   sprintf(nBlocks,"ab%d",N++);
   mBlock = geom->MakeBox(nBlocks,Iron,18,10,2);
   mBlock->SetLineColor(8);   
   {
   top->AddNodeOverlap(mBlock,1,new TGeoCombiTrans(-270+(k*100),-111,550, new TGeoRotation("r1",0,-45,0)));

   }
   k++;
}
   i++; k=0;
}




k=0; i=0;

while (i<5){   
while(k<6){
   sprintf(nBlocks,"ab%d",N++);
   mBlock = geom->MakeBox(nBlocks,Iron,18,10,2);
   mBlock->SetLineColor(8);   
   {
   top->AddNodeOverlap(mBlock,1,new TGeoCombiTrans(-270+(k*100),111,550, new TGeoRotation("r1",0,45,0)));

   }
   k++;
}
   i++; k=0;
}


   sprintf(nBlocks,"ab%d",N++);
   mBlock = geom->MakeBox(nBlocks, Iron, 18,10,2);
   mBlock->SetLineColor(8);   
   top->AddNodeOverlap(mBlock,1,new TGeoCombiTrans(336,0,550, new TGeoRotation("r1",90,-45,0)));



   sprintf(nBlocks,"ab%d",N++);
   mBlock = geom->MakeBox(nBlocks, Iron, 18,10,2);
   mBlock->SetLineColor(8);   
   top->AddNodeOverlap(mBlock,1,new TGeoCombiTrans(-336,0,550, new TGeoRotation("r1",90,45,0)));




//                  |           |           |            |           |



   sprintf(nBlocks,"ab%d",N++);
   mBlock = geom->MakeBox(nBlocks, Iron, 300,75,40);
   mBlock->SetLineColor(45);   
   top->AddNodeOverlap(mBlock,1,new TGeoCombiTrans(0,0,450, new TGeoRotation("r1",0,0,0)));



//kiwa
   sprintf(nBlocks,"ab%d",N++);
   mBlock = geom->MakeBox(nBlocks, Iron, 305,80,2.5);
   mBlock->SetLineColor(10);   
   top->AddNodeOverlap(mBlock,1,new TGeoTranslation(0,0,430));




  top->SetVisibility(0);
  geom->CloseGeometry();

  top->Draw("ogl");
}

//.........这里部分代码省略.........
  const double niMean = hIons->GetMean();
  std::cout << "Mean number of ions: " << niMean << "\n";

  std::cout << "Mean number of electrons on plastic: "
            << sumElectronsPlastic / nEvents << "\n";
  std::cout << "Mean number of ions on plastic: "
            << sumIonsPlastic / nEvents << "\n";
 
  std::cout << "Electron endpoints:\n";
  const double fUpperMetal = sumElectronsUpperMetal / sumElectronsTotal;
  const double fPlastic = sumElectronsPlastic / sumElectronsTotal;
  const double fLowerMetal = sumElectronsLowerMetal / sumElectronsTotal;
  const double fTransfer = sumElectronsTransfer / sumElectronsTotal;
  const double fOther = sumElectronsOther / sumElectronsTotal;
  std::cout << "    upper metal: " << fUpperMetal * 100. << "%\n";
  std::cout << "    plastic:     " << fPlastic * 100. << "%\n";
  std::cout << "    lower metal: " << fLowerMetal * 100. << "%\n";
  std::cout << "    transfer:    " << fTransfer * 100. << "%\n";
  std::cout << "    other:       " << fOther * 100. << "%\n";

  TCanvas* cD = new TCanvas();
  const bool plotGeo = true;
  if (plotGeo && plotDrift) {
    // Build the geometry in Root.
    TGeoManager* geoman = new TGeoManager("world", "geometry");
    TGeoMaterial* matVacuum = new TGeoMaterial("Vacuum", 0, 0, 0);
    TGeoMedium* medVacuum = new TGeoMedium("Vacuum", 1, matVacuum);
    TGeoMaterial* matKapton = new TGeoMaterial("Kapton", 12, 6, 1.42);
    TGeoMedium* medKapton = new TGeoMedium("Kapton", 2, matKapton);
    TGeoMaterial* matCopper = new TGeoMaterial("Copper", 63, 29, 8.94);
    TGeoMedium* medCopper = new TGeoMedium("Copper", 3, matCopper);
    TGeoVolume* volTop = geoman->MakeBox("TOP", 
                                         medVacuum, pitch, pitch, 0.02);
    volTop->SetVisibility(0);
    TGeoBBox* shpKapton = new TGeoBBox("K", pitch / 2., 
                                            pitch / 2., 
                                            kapton / 2.);
    TGeoPcon* shpHole = new TGeoPcon("H", 0., 360., 3);
    shpHole->DefineSection(0, -kapton / 2., 0., outdia / 2.);
    shpHole->DefineSection(1,           0., 0., middia / 2.);
    shpHole->DefineSection(2,  kapton / 2., 0., outdia / 2.);

    TGeoCompositeShape* shpGem = new TGeoCompositeShape("G", "K - H");
    TGeoVolume* volKapton = new TGeoVolume("Kapton", shpGem, medKapton);
    volKapton->SetLineColor(kGreen);
    volKapton->SetTransparency(50);

    TGeoBBox* shpMetal = new TGeoBBox("M", pitch / 2., 
                                           pitch / 2., 
                                           metal / 2.);
    TGeoTube* shpTube = new TGeoTube("T", 0., outdia / 2., metal / 2.);
    TGeoCompositeShape* shpElectrode = new TGeoCompositeShape("E", "M - T");
    TGeoVolume* volElectrode = new TGeoVolume("Electrode", 
                                              shpElectrode, medCopper);
    volElectrode->SetLineColor(kBlue);
    volElectrode->SetTransparency(50);

    TGeoVolumeAssembly* volGem = new TGeoVolumeAssembly("Gem");
    const double shift =  0.5 * (metal + kapton);
    volGem->AddNode(volKapton, 1);
    volGem->AddNode(volElectrode, 2, new TGeoTranslation(0., 0.,  shift));
    volGem->AddNode(volElectrode, 3, new TGeoTranslation(0., 0., -shift));

    volTop->AddNode(volGem, 1);
    volTop->AddNode(volGem, 2, new TGeoTranslation(-pitch, 0., 0.));
    volTop->AddNode(volGem, 3, new TGeoTranslation(+pitch, 0., 0.));