diff -u -r1.4 -r1.5
--- TrackUtils.java	27 Aug 2012 20:02:04 -0000	1.4
+++ TrackUtils.java	28 Sep 2012 22:07:28 -0000	1.5
@@ -3,14 +3,22 @@

 //--- hep ---//
 import hep.physics.vec.BasicHep3Vector;
 import hep.physics.vec.Hep3Vector;

+import hep.physics.vec.VecOp;
+import java.util.List;

 
 //--- org.lcsim ---//
 import org.lcsim.event.Track;

+import org.lcsim.event.TrackState;
+import org.lcsim.fit.helicaltrack.HelicalTrackFit;
+import org.lcsim.fit.helicaltrack.HelicalTrackStrip;
+import org.lcsim.fit.helicaltrack.HelixUtils;
+import org.lcsim.recon.tracking.seedtracker.SeedCandidate;
+import org.lcsim.recon.tracking.seedtracker.SeedTrack;

 
 /**
  * 
  * @author Omar Moreno <[log in to unmask]>

- * @version $Id: TrackUtils.java,v 1.4 2012/08/27 20:02:04 meeg Exp $

+ * @version $Id: TrackUtils.java,v 1.5 2012/09/28 22:07:28 phansson Exp $

  * TODO: Switch to JLab coordinates
  */
 

@@ -194,6 +202,63 @@

 		return new BasicHep3Vector(x, y, z);
 	}
 	

+        
+        
+        public double calculateHelixInterceptXPlane(HelicalTrackFit helfit, HelicalTrackStrip strip) {
+            /*
+            * Calculate the interception path length on the helix 
+            * where the track fit and the plane (where the strip is located) intercepts 
+            */
+            boolean _DEBUG = false;
+
+            HelicalTrackFit cfit = helfit;
+            if(cfit==null) {
+                SeedTrack st = (SeedTrack) track;
+                SeedCandidate seed = st.getSeedCandidate();
+                cfit = seed.getHelix();
+            }
+            if(_DEBUG) {
+                System.out.println(this.getClass().getSimpleName() + ": calculateHelixIntercept ---");
+                System.out.println(this.getClass().getSimpleName() + ": Track curvatute " + cfit.curvature() + " phi0 " + cfit.phi0());
+            }
+            //Get the origin of the plane
+            Hep3Vector org = strip.origin();
+            if(_DEBUG) System.out.println(this.getClass().getSimpleName() + ": origin of plane " + org.toString());
+
+            //Get the point on the helix at the origin
+            double xint = org.x();
+            double s = HelixUtils.PathToXPlane(cfit, xint,0,0).get(0);
+            if(_DEBUG) System.out.println(this.getClass().getSimpleName() + ": xint " + xint + "  s " + s );
+
+            //Calculate that point in space
+            Hep3Vector pos_xint = HelixUtils.PointOnHelix(cfit, s);
+            if(_DEBUG) System.out.println(this.getClass().getSimpleName() + ": xint position " + pos_xint.toString());
+
+            //Create a vector that points from the origin to that point
+            Hep3Vector vec_xint = VecOp.sub(pos_xint, org);
+            if(_DEBUG) System.out.println(this.getClass().getSimpleName() + ": vec_xint " + vec_xint.toString());
+
+            //Get the v in global coordinates
+            // v tells how the unmeasured coordinate is oriented in the tracking frame
+            Hep3Vector v = strip.v();
+            if(_DEBUG) System.out.println(this.getClass().getSimpleName() + ": v " + v.toString());
+
+            // We are basically looking for the point where v and track intercepts in the x-y plane
+            // Assuming that the track travels parallel to the x axis we can calculate the 
+            // the correction to xint by scaling
+            // NEED TO TAKE INTO ACCOUNT THE REAL TRACK TRAJECTORY!!
+            double x_corr = vec_xint.y() * v.x()/v.y();
+            if(_DEBUG) System.out.println(this.getClass().getSimpleName() + ": vy " + vec_xint.y() + " vx/vy " + v.x()/v.y() + " -> " +  "x_corr " + x_corr);
+            double xint_new = xint + x_corr;
+            if(_DEBUG) System.out.println(this.getClass().getSimpleName() + ": final xint_new " + xint_new);
+
+            return xint_new;
+
+
+        }
+
+        
+        

 	/**
 	 * 
 	 */