- add DetectorData inforamtion to ZPlanarTracker (needed for Gear )

 - fixed bug in MaterialManager (protect against empty material list)
 - allow missing detectors in createGearForILD

DDRec/src/MaterialManager.cpp

@@ -114,6 +114,13 @@ namespace DD4hep {
 	  node1=node2;
 	}
 	
+
+	//fg: protect against empty list:
+	if( _mV.empty() ){
+	  _mV.push_back( std::make_pair( Material( node1->GetMedium() ), totDist  )  ) ; 
+	}
+
+
 	_tgeoMgr->ClearTracks();
 	_tgeoMgr->CleanGarbage();
 	

examples/SimpleDetector/compact/Simple_ILD.xml

@@ -86,7 +86,7 @@
         </layer>
       </detector>
 
-      <detector name="SIT" type="ZPlanarTracker" vis="SITVis" id="1" limits="Tracker_limits" readout="SITCollection" insideTrackingVolume="true">
+      <detector name="SIT" type="ZPlanarTracker" vis="SITVis" id="2" limits="Tracker_limits" readout="SITCollection" insideTrackingVolume="true">
         <layer nLadders="10" phi0="0.000000000e+00" id="0">
           <ladder distance="1.531000000e+02*mm" thickness="1.000000000e+00*mm" width="9.916044311e+01*mm" length="3.680000000e+02*mm" offset="0.000000000e+00*mm"  material="CarbonFiber" /> 
           <sensitive distance="1.529000000e+02*mm" thickness="2.000000000e-01*mm" width="9.916044311e+01*mm" length="3.680000000e+02*mm" offset="0.000000000e+00*mm" material="G4_Si"/>

examples/SimpleDetector/src/ZPlanarTracker_geo.cpp

@@ -11,6 +11,8 @@
 #include "DD4hep/DetFactoryHelper.h"
 
 #include "DDRec/Surface.h"
+#include "DDRec/DetectorData.h"
+
 
 using namespace DD4hep;
 using namespace DD4hep::Geometry;
@@ -31,6 +33,8 @@ static Ref_t create_element(LCDD& lcdd, xml_h e, SensitiveDetector sens)  {
 
   PlacedVolume pv;
   
+  DDRec::ZPlanarData*  zPlanarData = new DDRec::ZPlanarData ;
+
   //=========  loop over layer elements in xml  ======================================
 
   for(xml_coll_t c(e, _U(layer) ); c; ++c)  {
@@ -85,6 +89,30 @@ static Ref_t create_element(LCDD& lcdd, xml_h e, SensitiveDetector sens)  {
 
 
     //-----------------------------------
+    //  store the data in an extension to be used for reconstruction 
+    DDRec::ZPlanarData::LayerLayout thisLayer ;
+
+    thisLayer.sensorsPerLadder =  1 ; // for now only one planar sensor
+    thisLayer.lengthSensor     =  2. * sens_zhalf ;
+    
+    thisLayer.distanceSupport  = supp_distance ;
+    thisLayer.offsetSupport    = supp_offset ;
+    thisLayer.thicknessSupport = supp_thickness ;
+    thisLayer.zHalfSupport     = supp_zhalf ;
+    thisLayer.widthSupport     = supp_width ;      
+    
+    thisLayer.distanceSensitive  = sens_distance ;  
+    thisLayer.offsetSensitive    = sens_offset ;	  
+    thisLayer.thicknessSensitive = sens_thickness ; 
+    thisLayer.zHalfSensitive     = sens_zhalf ;	  
+    thisLayer.widthSensitive     = sens_width ;     
+    
+    thisLayer.ladderNumber =  nLadders ;
+    thisLayer.phi0         =  phi0 ;
+    
+    zPlanarData->layers.push_back( thisLayer ) ;
+    //-----------------------------------
+
 
     Material supp_mat     = lcdd.material( supp_matS ) ;
     Material sens_mat     = lcdd.material( sens_matS ) ;
@@ -170,6 +198,9 @@ static Ref_t create_element(LCDD& lcdd, xml_h e, SensitiveDetector sens)  {
 
   }
 
+
+  tracker.addExtension< DDRec::ZPlanarData >( zPlanarData ) ;
+  
   Volume mother =  lcdd.pickMotherVolume( tracker ) ;
 
   pv = mother.placeVolume(assembly);