diff -u -r1.7 -r1.8
--- Layer.java	21 Sep 2005 01:37:17 -0000	1.7
+++ Layer.java	6 Apr 2006 17:35:20 -0000	1.8
@@ -66,7 +66,7 @@

     
     public double getThicknessToSensitiveMid()
     {

-        int i = findIndexOfFirstSensitiveSlice();

+        int i = indexOfFirstSensor();

         
         double thickness = 0.;
         

@@ -86,7 +86,7 @@

     
     public double getThicknessToSensitive()
     {

-        int i = findIndexOfFirstSensitiveSlice();

+        int i = indexOfFirstSensor();

         
         double thickness = 0.;
         

@@ -117,7 +117,12 @@

         return slices;
     }
     

-    public int findIndexOfFirstSensitiveSlice()

+    public double getSensorThickness()
+    {
+    	return slices.get(indexOfFirstSensor()).getThickness();
+    }
+    
+    public int indexOfFirstSensor()

     {
         int i = 0;
         boolean fnd = false;

diff -u -r1.8 -r1.9
--- LayerStack.java	15 Mar 2006 09:54:02 -0000	1.8
+++ LayerStack.java	6 Apr 2006 17:35:20 -0000	1.9
@@ -80,7 +80,7 @@

     {
         return getThicknessToLayerBack(i) - layers.get(i).getThickness() / 2;
     }

-    

+        

     public double getThicknessToLayerFront(int i)
     {
         return getThicknessToLayerBack(i) - getLayer(i).getThickness();

diff -u -r1.3 -r1.4
--- Layering.java	26 Aug 2005 02:37:04 -0000	1.3
+++ Layering.java	6 Apr 2006 17:35:21 -0000	1.4
@@ -38,6 +38,11 @@

         return getLayerStack().getThicknessToLayerFront(layer) + offset;
     }
     

+    public double getDistanceToLayerBack(int layer)
+    {
+    	return getLayerStack().getThicknessToLayerBack(layer) + offset;
+    }
+    

     /** alias to getLayerStack() */
     public LayerStack getLayers()
     {

@@ -80,6 +85,16 @@

                getLayerStack().getLayer(layer).getThicknessToSensitiveMid();
     }
     

+    public double getDistanceToLayerSensorFront(int layer)
+    {
+    	return getDistanceToLayer(layer) + getLayerStack().getLayer(layer).getThicknessToSensitive();
+    }
+    
+    public double getDistanceToLayerSensorBack(int layer)
+    {    	
+    	return getDistanceToLayerSensorFront(layer) + getLayer(layer).getSensorThickness();
+    }
+            

     public void setOffset(double o)
     {
         offset = o;