void EUTelGeometryTelescopeGeoDescription::translateSiPlane2TGeo(TGeoVolume* pvolumeWorld, int SensorId ) {
	double xc, yc, zc;   // volume center position 
	double alpha, beta, gamma;
	double rotRef1, rotRef2, rotRef3, rotRef4;

	std::stringstream strId;
	strId << SensorId;

	// Get sensor center position
	xc = siPlaneXPosition( SensorId );
	yc = siPlaneYPosition( SensorId );
	zc = siPlaneZPosition( SensorId );

	// Get sensor orientation
	alpha = siPlaneXRotation( SensorId ); //  in degrees !
	beta  = siPlaneYRotation( SensorId ); // 
	gamma = siPlaneZRotation( SensorId ); // 

	rotRef1 = siPlaneRotation1( SensorId );
	rotRef2 = siPlaneRotation2( SensorId );
	rotRef3 = siPlaneRotation3( SensorId );
	rotRef4 = siPlaneRotation4( SensorId );

	//We must check that the input is correct. Since this is a combination of initial rotations and reflections the determinate must be 1 or -1
	float determinant = rotRef1*rotRef4 - rotRef2*rotRef3  ;
	if(determinant==1 or determinant==-1) { 
		streamlog_out(DEBUG5) << "SensorID: " << SensorId << ". Determinant =  " <<determinant <<"  This is the correct determinate for this transformation." << std::endl;   
	} else {
		streamlog_out(ERROR5) << "SensorID: " << SensorId << ". Determinant =  " <<determinant << std::endl;   
		throw(lcio::Exception("The initial rotation and reflection matrix does not have determinant of 1 or -1. Gear file input must be wrong.")); 	
	}
	//Create spatial TGeoTranslation object.
	std::string stTranslationName = "matrixTranslationSensor";
	stTranslationName.append( strId.str() );
	TGeoTranslation* pMatrixTrans = new TGeoTranslation( stTranslationName.c_str(), xc, yc, zc );
	//ALL clsses deriving from TGeoMatrix are not owned by the ROOT geometry manager, invoking RegisterYourself() transfers
	//ownership and thus ROOT will clean up
	pMatrixTrans->RegisterYourself();      

	//Create TGeoRotation object. 
	//Translations are of course just positional changes in the global frame.
	//Note that each subsequent rotation is using the new coordinate system of the last transformation all the way back to the global frame.
	//The way to think about this is that each rotation is the multiplication of the last rotation matrix by a new one.
	//The order is:
	//Integer Z rotation and reflections.
	//Z rotations specified by in degrees.
	//X rotations 
	//Y rotations
	TGeoRotation* pMatrixRotRefCombined = new TGeoRotation();
	//We have to ensure that we retain a right handed coordinate system, i.e. if we only flip the x or y axis, we have to also flip the z-axis. If we flip both we have to flip twice.	
	double integerRotationsAndReflections[9]={rotRef1,rotRef2,0,rotRef3,rotRef4,0,0,0, determinant};
	pMatrixRotRefCombined->SetMatrix(integerRotationsAndReflections);
	std::cout << "Rotating plane " << SensorId << " to gamma: " << gamma << std::endl;
	pMatrixRotRefCombined->RotateZ(gamma);//Z Rotation (degrees)//This will again rotate a vector around z axis usign the right hand rule.  
	pMatrixRotRefCombined->RotateX(alpha);//X Rotations (degrees)//This will rotate a vector usign the right hand rule round the x-axis
	pMatrixRotRefCombined->RotateY(beta);//Y Rotations (degrees)//Same again for Y axis
	pMatrixRotRefCombined->RegisterYourself();//We must allow the matrix to be used by the TGeo manager.
	// Combined translation and orientation
	TGeoCombiTrans* combi = new TGeoCombiTrans( *pMatrixTrans, *pMatrixRotRefCombined );
	//This is to print to screen the rotation and translation matrices used to transform from local to global frame.
	streamlog_out(MESSAGE9) << "THESE MATRICES ARE USED TO TAKE A POINT IN THE LOCAL FRAME AND MOVE IT TO THE GLOBAL FRAME."  << std::endl;   
	streamlog_out(MESSAGE9) << "SensorID: " << SensorId << " Rotation/Reflection matrix for this object."  << std::endl;   
	const double* rotationMatrix =  combi->GetRotationMatrix();	
	streamlog_out(MESSAGE9) << std::setw(10) <<rotationMatrix[0]<<"  "<<rotationMatrix[1]<<"   "<<rotationMatrix[2]<< std::endl;
	streamlog_out(MESSAGE9) << std::setw(10) <<rotationMatrix[3]<<"  "<<rotationMatrix[4]<<"   "<<rotationMatrix[5]<< std::endl;
	streamlog_out(MESSAGE9) << std::setw(10) <<rotationMatrix[6]<<"  "<<rotationMatrix[7]<<"   "<<rotationMatrix[8]<< std::endl;

	//streamlog_out(MESSAGE9) << std::setw(10) <<rotationMatrix[0] << std::setw(10) <<rotationMatrix[1]<< std::setw(10) <<rotationMatrix[2]<< std::setw(10)<< std::endl<< std::endl; 
	//streamlog_out(MESSAGE9) << std::setw(10) <<rotationMatrix[3] << std::setw(10) <<rotationMatrix[4]<< std::setw(10) <<rotationMatrix[5]<< std::setw(10)<< std::endl<< std::endl; 
	//streamlog_out(MESSAGE9) << std::setw(10) <<rotationMatrix[6] << std::setw(10) <<rotationMatrix[7]<< std::setw(10) <<rotationMatrix[8]<< std::setw(10)<< std::endl<< std::endl; 
	const double* translationMatrix =  combi->GetTranslation();	
	streamlog_out(MESSAGE9) << "SensorID: " << SensorId << " Translation vector for this object."  << std::endl;   
	streamlog_out(MESSAGE9) << std::setw(10) <<translationMatrix[0] << std::setw(10) <<translationMatrix[1]<< std::setw(10) <<translationMatrix[2]<< std::setw(10)<< std::endl; 

	combi->RegisterYourself();   
	
	// Construct object medium. Required for radiation length determination
	// assume SILICON, though all information except of radiation length is ignored
	double a       = 28.085500;     
	double z       = 14.000000;
	double density = 2.330000;
	double radl    = siPlaneRadLength( SensorId );
	double absl    = 45.753206;
	std::string stMatName = "materialSensor";
	stMatName.append( strId.str() );
	TGeoMaterial* pMat = new TGeoMaterial( stMatName.c_str(), a, z, density, -radl, absl );
	pMat->SetIndex( 1 );
	// Medium: medium_Sensor_SILICON
	int numed   = 0;  // medium number
	double par[8];
	par[0]  = 0.000000; // isvol
	par[1]  = 0.000000; // ifield
	par[2]  = 0.000000; // fieldm
	par[3]  = 0.000000; // tmaxfd
	par[4]  = 0.000000; // stemax
	par[5]  = 0.000000; // deemax
	par[6]  = 0.000000; // epsil
	par[7]  = 0.000000; // stmin
	std::string stMedName = "mediumSensor";
	stMedName.append( strId.str() );
	TGeoMedium* pMed = new TGeoMedium( stMedName.c_str(), numed, pMat, par );

	// Construct object shape
	// Shape: Box type: TGeoBBox
	// TGeo requires half-width of box side
	Double_t dx = siPlaneXSize( SensorId ) / 2.;
	Double_t dy = siPlaneYSize( SensorId ) / 2.;
	Double_t dz = siPlaneZSize( SensorId ) / 2.;
	TGeoShape *pBoxSensor = new TGeoBBox( "BoxSensor", dx, dy, dz );

	std::cout << "Box for sensor: " << SensorId << " is: " << dx << "|" << dy  << "|" << dz << '\n';

	// Geometry navigation package requires following names for objects that have an ID  name:ID
	std::string stVolName = "volume_SensorID:";
	stVolName.append( strId.str() );

	_planePath.insert( std::make_pair(SensorId, "/volume_World_1/"+stVolName+"_1") );

	TGeoVolume* pvolumeSensor = new TGeoVolume( stVolName.c_str(), pBoxSensor, pMed );
	pvolumeSensor->SetVisLeaves( kTRUE );
	pvolumeWorld->AddNode(pvolumeSensor, 1/*(SensorId)*/, combi);

	//this line tells the pixel geometry manager to load the pixel geometry into the plane			
	streamlog_out(DEBUG1) << " sensorID: " << SensorId << " " << stVolName << std::endl;   
	std::string name = geoLibName(SensorId);

	if( name == "CAST" ) {
		_pixGeoMgr->addCastedPlane( SensorId, siPlaneXNpixels(SensorId), siPlaneYNpixels(SensorId), siPlaneXSize(SensorId), siPlaneYSize(SensorId), siPlaneZSize(SensorId), siPlaneRadLength(SensorId), stVolName);
	} else {
		_pixGeoMgr->addPlane( SensorId, name, stVolName);
		updatePlaneInfo(SensorId);
	}
}
/**
 * Initialise ROOT geometry objects from GEAR objects
 * 
 * @param geomName name of ROOT geometry object
 * @param dumpRoot dump automatically generated ROOT geometry file for further inspection
 */
void EUTelGeometryTelescopeGeoDescription::initializeTGeoDescription( std::string& geomName, bool dumpRoot = false ) {
//    #ifdef USE_TGEO
    // get access to ROOT's geometry manager
    
	if( _isGeoInitialized )
	{
		streamlog_out( WARNING3 ) << "EUTelGeometryTelescopeGeoDescription: Geometry already initialized, using old initialization" << std::endl;
		return;
	}
	else
	{
    		_geoManager = new TGeoManager("Telescope", "v0.1");
	}

	if( !_geoManager )
	{
		streamlog_out( ERROR3 ) << "Can't instantiate ROOT TGeoManager " << std::endl;
		return;
	}
   
    
    // Create top world volume containing telescope/DUT geometry
    
    
    // Create air mixture
    // see http://pdg.lbl.gov/2013/AtomicNuclearProperties/HTML_PAGES/104.html
    double air_density = 1.2e-3;         // g/cm^3
    double air_radlen  = 36.62;          // g/cm^2
    TGeoMixture* pMatAir = new TGeoMixture("AIR",3,air_density);
    pMatAir->DefineElement(0, 14.007, 7.,  0.755267 );     //Nitrogen
    pMatAir->DefineElement(1, 15.999, 8.,  0.231781 );     //Oxygen
    pMatAir->DefineElement(2, 39.948, 18., 0.012827 );     //Argon
    pMatAir->DefineElement(3, 12.011, 6.,  0.000124 );     //Carbon
    pMatAir->SetRadLen( air_radlen );
    // Medium: medium_World_AIR
    TGeoMedium* pMedAir = new TGeoMedium("medium_World_AIR", 3, pMatAir );

    // The World is the 10 x 10m x 10m box filled with air mixture
    Double_t dx,dy,dz;
    dx = 5000.000000; // [mm]
    dy = 5000.000000; // [mm]
    dz = 5000.000000; // [mm]
    TGeoShape *pBoxWorld = new TGeoBBox("Box_World", dx,dy,dz);
    // Volume: volume_World
    TGeoVolume* pvolumeWorld = new TGeoVolume("volume_World",pBoxWorld, pMedAir);
    pvolumeWorld->SetLineColor(4);
    pvolumeWorld->SetLineWidth(3);
    pvolumeWorld->SetVisLeaves(kTRUE);

   // Set top volume of geometry
   gGeoManager->SetTopVolume( pvolumeWorld );
   
 
   
   // Iterate over registered GEAR objects and construct their TGeo representation
   
   const Double_t PI = 3.141592653589793;
   const Double_t DEG = 180./PI;
   
   double xc, yc, zc;   // volume center position 
   double alpha, beta, gamma;
   
   IntVec::const_iterator itrPlaneId;
   for ( itrPlaneId = _sensorIDVec.begin(); itrPlaneId != _sensorIDVec.end(); ++itrPlaneId ) {
       
       std::stringstream strId;
       strId << *itrPlaneId;
       
       // Get sensor center position
       xc = siPlaneXPosition( *itrPlaneId );
       yc = siPlaneYPosition( *itrPlaneId );
       zc = siPlaneZPosition( *itrPlaneId );
       
       // Get sensor orientation
       alpha = siPlaneXRotation( *itrPlaneId ); // [rad]
       beta  = siPlaneYRotation( *itrPlaneId ); // [rad]
       gamma = siPlaneZRotation( *itrPlaneId ); // [rad]
       
       // Spatial translations of the sensor center
       string stTranslationName = "matrixTranslationSensor";
       stTranslationName.append( strId.str() );
       TGeoTranslation* pMatrixTrans = new TGeoTranslation( stTranslationName.c_str(), xc, yc, zc );
       //ALL clsses deriving from TGeoMatrix are not owned by the ROOT geometry manager, invoking RegisterYourself() transfers
       //ownership and thus ROOT will clean up
       pMatrixTrans->RegisterYourself();      
       
       // Spatial rotation around sensor center
       // TGeoRotation requires Euler angles in degrees
       string stRotationName = "matrixRotationSensorX";
       stRotationName.append( strId.str() );
       TGeoRotation* pMatrixRotX = new TGeoRotation( stRotationName.c_str(), 0.,  alpha*DEG, 0.);                // around X axis
       stRotationName = "matrixRotationSensorY";
       stRotationName.append( strId.str() );
       TGeoRotation* pMatrixRotY = new TGeoRotation( stRotationName.c_str(), 90., beta*DEG,  0.);                // around Y axis (combination of rotation around Z axis and new X axis)
       stRotationName = "matrixRotationSensorBackY";
       stRotationName.append( strId.str() );
       TGeoRotation* pMatrixRotY1 = new TGeoRotation( stRotationName.c_str(), -90., 0.,  0.);                    // restoration of original orientation (valid in small angle approximataion ~< 15 deg)
       stRotationName = "matrixRotationSensorZ";
       stRotationName.append( strId.str() );
       TGeoRotation* pMatrixRotZ = new TGeoRotation( stRotationName.c_str(), 0. , 0.,        gamma*DEG);         // around Z axis
       
       // Combined rotation in several steps
       TGeoRotation* pMatrixRot = new TGeoRotation( *pMatrixRotX );
       pMatrixRot->MultiplyBy( pMatrixRotY );
       pMatrixRot->MultiplyBy( pMatrixRotY1 );
       pMatrixRot->MultiplyBy( pMatrixRotZ );
       pMatrixRot->RegisterYourself();      
      
       pMatrixRotX->RegisterYourself();
       pMatrixRotY->RegisterYourself();
       pMatrixRotY1->RegisterYourself(); 
       pMatrixRotZ->RegisterYourself();
 
       // Combined translation and orientation
       TGeoCombiTrans* combi = new TGeoCombiTrans( *pMatrixTrans, *pMatrixRot );
       combi->RegisterYourself();   
 
       // Construction of sensor objects
       
       // Construct object medium. Required for radiation length determination

       // assume SILICON, though all information except of radiation length is ignored
       double a       = 28.085500;     
       double z       = 14.000000;
       double density = 2.330000;
       double radl    = siPlaneMediumRadLen( *itrPlaneId );
       double absl    = 45.753206;
       string stMatName = "materialSensor";
       stMatName.append( strId.str() );
       TGeoMaterial* pMat = new TGeoMaterial( stMatName.c_str(), a, z, density, radl, absl );
       pMat->SetIndex( 1 );
       // Medium: medium_Sensor_SILICON
       int numed   = 0;  // medium number
       double par[8];
       par[0]  = 0.000000; // isvol
       par[1]  = 0.000000; // ifield
       par[2]  = 0.000000; // fieldm
       par[3]  = 0.000000; // tmaxfd
       par[4]  = 0.000000; // stemax
       par[5]  = 0.000000; // deemax
       par[6]  = 0.000000; // epsil
       par[7]  = 0.000000; // stmin
       string stMedName = "mediumSensor";
       stMedName.append( strId.str() );
       TGeoMedium* pMed = new TGeoMedium( stMedName.c_str(), numed, pMat, par );
       
       // Construct object shape
       // Shape: Box type: TGeoBBox
       // TGeo requires half-width of box side
       dx = siPlaneXSize( *itrPlaneId ) / 2.;
       dy = siPlaneYSize( *itrPlaneId ) / 2.;
       dz = siPlaneZSize( *itrPlaneId ) / 2.;
       TGeoShape *pBoxSensor = new TGeoBBox( "BoxSensor", dx, dy, dz );
       // Volume: volume_Sensor1
       
       // Geometry navigation package requires following names for objects that have an ID
       // name:ID
       string stVolName = "volume_SensorID:";
       stVolName.append( strId.str() );

		_planePath.insert( std::make_pair(*itrPlaneId, "/volume_World_1/"+stVolName+"_1") );

       TGeoVolume* pvolumeSensor = new TGeoVolume( stVolName.c_str(), pBoxSensor, pMed );
       pvolumeSensor->SetVisLeaves( kTRUE );
       pvolumeWorld->AddNode(pvolumeSensor, 1/*(*itrPlaneId)*/, combi);
	
	//this line tells the pixel geometry manager to load the pixel geometry into the plane			
        _pixGeoMgr->addPlane( *itrPlaneId, geoLibName( *itrPlaneId), stVolName);
   } // loop over sensorID

    _geoManager->CloseGeometry();
    _isGeoInitialized = true;
    // Dump ROOT TGeo object into file
    if ( dumpRoot ) _geoManager->Export( geomName.c_str() );

//    #endif //USE_TGEO
    return;
}