OpenGL viewer and transparency

ROOT
10

Hi,

This is probably what you want:

int numtubes = 5;
Float_t rintube[5] = {2.35, 2.35, 2.35, 2.35, 2.35};
Float_t d_wire[5] =  {0.01, 0.01, 0.01, 0.01, 0.01};
Float_t z_min[5] = {-40.,-40.,-40.,-40.,-40.};
Float_t z_max[5] = { 40., 40., 40., 40., 40.};
Float_t x_f0[5] = {0.,-40.,-20., 20., 40.};
Float_t ytubes[5] = {10.,0.,0.,20.,0.};

void lay_ch()
{   
   TGeoManager *manager = new TGeoManager("Chamber Layout", "Chamber Layout");
   TGeoMaterial *mat = new TGeoMaterial("Vacuum", 0.,0.,0.);
   TGeoMaterial *tmat = new TGeoMaterial("TubeMat", 26.98,13.,2.700);
   tmat->SetTransparency(50);

   TGeoMaterial *wmat = new TGeoMaterial("WireMat", 63.546,29.,8.920);
   TGeoMedium *med = new TGeoMedium("Vacuum", 0, mat);
   TGeoMedium *tmed = new TGeoMedium("TubeMed", 0, tmat);
   TGeoMedium *wmed = new TGeoMedium("WireMed", 0, wmat);
   
   TGeoVolume *top = manager->MakeBox("Top",med,150.,183.65,120.);
   manager->SetTopVolume(top);

   TGeoVolume **tube = new TGeoVolume*[numtubes];
   TGeoVolume **wire = new TGeoVolume*[numtubes];
   TGeoTranslation T;
   TGeoRotation R;
   TGeoCombiTrans **M = new TGeoCombiTrans *[numtubes];
   char tname[30], wname[30];
   for (int i=0; i<numtubes; i++)
      {
      T.SetTranslation(x_f0[i], ytubes[i], 0.);
      R.SetAngles(0.,0.,0.);
      M[i]= new TGeoCombiTrans(T,R);
      
      sprintf(tname, "Tube[%i]",i);
      sprintf(wname, "wire[%i]",i);
      tube[i] = manager->MakeTube(tname,tmed,rintube[i],rintube[i]+0.15,z_max[i]-z_min[i]);
      wire[i] = manager->MakeTube(wname,wmed,0.,d_wire[i],z_max[i]-z_min[i]);
      
      tube[i]->SetLineColor(17);
   
      wire[i]->SetLineColor(46);
//      tube[i]->AddNode(wire[i],1);
      top->AddNode(tube[i],1,M[i]);
      top->AddNode(wire[i],1,M[i]);
      }

   manager->CloseGeometry();
   
   TCanvas *c3D = new TCanvas("c3D","Chamber Layout",1200,800);
   delete [] tube;
   delete [] wire;
   delete [] M;
   
   top->Draw("ogl");
}

Note that:

  • TGeo does not use SetFillColor/SetFillStyle - the line color is used also as fill color
  • you should not position a wire in the hole of a tube; any daughter volume should be contained inside the body of the mother volume. Rather position both with the same matrix in a common container.
  • to visualize in solid mode with transparency you have to use the OpenGL viewer and just use: TGeoMaterial::SetTransparency(0 to 100) or TGeoVolume::SetTransparency(). Note that a transparency>50 will make a volume invisible in the normal pad.
  • the changed macro above do produce transparent chambers - you see the wires only if you zoom (mouse wheel) since the wires are very thin.

Cheers,

1 Like