diff -u -r1.3 -r1.4
--- ShowerPointFinder.java	19 Aug 2008 14:57:36 -0000	1.3
+++ ShowerPointFinder.java	6 Sep 2008 23:47:39 -0000	1.4
@@ -28,13 +28,13 @@

 import org.lcsim.util.decision.*;
 
     public class ShowerPointFinder{

-    protected LocalHelixExtrapolator m_extrap;

+    protected HelixExtrapolator m_extrap;

     protected Map<Track,Cluster> m_tracksMatchedToClusters;
     protected Set<CalorimeterHit> m_allhits;
     protected int exam = 0; //to test neighbour
     protected boolean debug = false;
 

-    public ShowerPointFinder(LocalHelixExtrapolator extrap, Set<CalorimeterHit> allHits, Map<Track,Cluster> tracksMatchedToClusters ) {

+    public ShowerPointFinder(HelixExtrapolator extrap, Set<CalorimeterHit> allHits, Map<Track,Cluster> tracksMatchedToClusters ) {

 		m_extrap = extrap;
 		m_allhits = allHits; 
 		m_tracksMatchedToClusters = tracksMatchedToClusters;

@@ -45,7 +45,11 @@

 	Map<Track, BasicCluster> MapTrkToMIP = new HashMap<Track, BasicCluster>();
 	for(Track tr : m_tracksMatchedToClusters.keySet()){ 
             BasicCluster mipclus = new BasicCluster();  //for new mip cluster   

-	    Hep3Vector interceptPoint = m_extrap.performExtrapolation(tr); //for debuging

+	    HelixExtrapolationResult result = m_extrap.performExtrapolation(tr);
+	    Hep3Vector interceptPoint = null; // for debugging
+	    if (result != null) {
+		interceptPoint = result.getInterceptPoint();
+	    }

 	    Cluster seed = m_tracksMatchedToClusters.get(tr);
 
 	    if(debug){

@@ -120,10 +124,20 @@

 		    if(EcalToHcal || InSide || EndToBarrelEcal || EndToBarrelHcal ){
 			Hep3Vector cur = VecOp.sub(curpos, last0);
 			Hep3Vector curUnit = VecOp.unit(cur);

-			Hep3Vector last = VecOp.sub(last0, last1);
-		        //Since there is only one hit we have at the first, we use a extrapolrated tangent vector 	
-			if(  mipclus.getCalorimeterHits().size() > 1) { last = VecOp.sub(last0, last1);}
-			else { last = m_extrap.getTangent();}

+			Hep3Vector last = null;
+			if (mipclus.getCalorimeterHits().size() > 1) { 
+			    last = VecOp.sub(last0, last1);
+			} else {
+			    //Since there is only one hit we have at the first, we use a extrapolrated tangent vector 	
+			    if (result != null) {
+				last = result.getTangent();
+			    }
+			    if (last == null) {
+				// No extrapolation info and only one hit -- fall back to using
+				// a straight line from the origin.
+				last = VecOp.sub(last0, new BasicHep3Vector(0,0,0));
+			    }
+			}

 			Hep3Vector lastUnit = VecOp.unit(last);
 			double a = Math.acos(VecOp.dot(lastUnit, curUnit));
 			double d = VecOp.sub(cur,last).magnitude();