class TTable3Points: public TTablePoints

   TTable3Points class is to create 3D view of any 3 columns of the TTable objects
   with one and the same "key column value".

   For example all values of the column "x[0]" "x[1]" "x[2]" of the 

 table
   from the rows with one and same "track_id" column value will be regarded
   as an image of one and the same "track".
   The last means all those points will be painted with one and the same 3D
   attributes like "color", "size", "style", "light","markers", "connections"  etc.

   The original TTable object must be pre-sorted by "key column" via TTableSorter
   class

 void   CreatePoints(Tg2t_tpc_hit *points)
 {
   g2t_tpc_hit_st *p = points->GetTable();

  TTable3Points *track = 0;
  TString tr;
  tr = "track_p";
  TTable &ttt = *((TTable *)points);
  // Track2Line MUST be on heap otherwise 3D view will crash just code leaves this
  // subroutine
  We will assemble all points by its "track_p" field.

  TTableSorter *Track2Line = new TTableSorter (ttt,"track_p");

  Int_t i = 0;
  Char_t buffer[10];
  Int_t ntracks = 0;
  const Int_t maxtracks = 5;
---------------------------- Fill tracks -------------------
  long currentId = -1;
  long newId =  0;
  g2t_tpc_hit_st *hitPoint = 0;
  TVolume *thisTrack[7] = {0,0,0,0,0,0,0}; // seven volumes for 7 different colors
  Int_t  MaxRowtoCount = 5000; // 5000;
  Int_t  MaxTracks = Track2Line->CountKeys();
  MaxTracks = 100;
  for (i=0;i<Track2Line->GetNRows() && ntracks <  MaxTracks ;i++)
  {
   hitPoint = p + Track2Line->GetIndex(i);
   newId =  hitPoint->track_p;
   if (newId != currentId)  { // The hit for the new track has been found

     const Char_t *xName = "x[0]";
     const Char_t *yName = "x[1]";
     const Char_t *zName = "x[2]";

     track =  new TTable3Points(Track2Line,(const void *)&newId,xName,yName,zName);

     // Create a shape for this node
     TPolyLineShape *trackShape  =  new TPolyLineShape(track);
     trackShape->SetVisibility(1);
     Int_t colorIndx = ntracks%7;
     trackShape->SetColorAttribute(colorIndx+kGreen);
     trackShape->SetLineStyle(1);
     trackShape->SetSizeAttribute(2);
     // Create a node to hold it
     if (!thisTrack[colorIndx])  {
         thisTrack[colorIndx] = new TVolume("hits","hits",trackShape);
         thisTrack[colorIndx]->Mark();
         thisTrack[colorIndx]->SetVisibility();
         TVolumePosition *pp = hall->Add(thisTrack[colorIndx]);
         if (!pp) printf(" no position %d\n",ntrack);
     }
     else
       thisTrack[colorIndx]->Add(trackShape);
     currentId = newId;
     ntracks++;
   }
 }