Make a geometry transparent

matevz · November 15, 2021, 4:27pm

No, you need to set transparency on each volume, as you do with color.

I was usually quite happy with what TGeoManager::DefaultColors() does, it makes volumes transparent based on their densiity:

github.com

root-project/root/blob/master/geom/geom/src/TGeoManager.cxx#L2103

    
      
             col[13] = kBlue-10;
             col[14] = kOrange+7;
             col[16] = kYellow+1;
             col[20] = kYellow-10;
             col[24] = col[25] = col[26] = kBlue-8;
             col[29] = kOrange+9;
             col[79] = kOrange-2;
          
          
   TGeoVolume *vol;
             TIter next(fVolumes);
             while ((vol=(TGeoVolume*)next())) {
                TGeoMedium *med = vol->GetMedium();
                if (!med) continue;
                TGeoMaterial *mat = med->GetMaterial();
                Int_t matZ = (Int_t)mat->GetZ();
                vol->SetLineColor(col[matZ]);
                if (mat->GetDensity()<0.1) vol->SetTransparency(60);
             }
          }
          
          
////////////////////////////////////////////////////////////////////////////////

Cheers,
Matevz