diff --git a/Detector/DetCEPCv4/src/tracker/VXD04_geo.cpp b/Detector/DetCEPCv4/src/tracker/VXD04_geo.cpp
index 9b13b09a490026901fabc8d868c3109f849afb4d..bec4117d8d72721a2c93c1bb9e5087a2d7847f54 100644
--- a/Detector/DetCEPCv4/src/tracker/VXD04_geo.cpp
+++ b/Detector/DetCEPCv4/src/tracker/VXD04_geo.cpp
@@ -323,7 +323,8 @@ static Ref_t create_element(Detector& theDetector, xml_h e, SensitiveDetector se
     
     phirot = (2*M_PI)/nb_ladder;
     
-    double ladder_clothest_approch = beryllium_ladder_block_thickness*2 +0.1;
+    //Notice: length unit in here is cm, by fucd
+    double ladder_clothest_approch = beryllium_ladder_block_thickness*2 +0.01;
 
     // calculate optimal offset, such that there is 0.1mm space between to the edge and the surface of two adjacent ladders.
     // in the case of ladders overlapped per superlayer
@@ -333,11 +334,16 @@ static Ref_t create_element(Detector& theDetector, xml_h e, SensitiveDetector se
       +(ladder_clothest_approch+cos(phirot)*2*(foam_spacer_thickness+active_silicon_thickness+flex_cable_thickness+metal_traces_thickness))/sin(phirot));
     */
     // in the case of ladders overlapped per layer
-      
+    /*
     double offset_phi=(1-cos(phirot))/sin(phirot)*layer_radius  
       -((ladder_width+(side_band_electronics_option*side_band_electronics_width/2.))
 	+(ladder_clothest_approch+cos(phirot)*2*(active_silicon_thickness+flex_cable_thickness+metal_traces_thickness-foam_spacer_thickness/2.0))/sin(phirot));
-      
+    */
+    // by fucd: same as CEPC_v4 in MokkaC 
+    double offset_phi=(1-cos(phirot))/sin(phirot)*layer_radius
+      -((ladder_width+(side_band_electronics_option*side_band_electronics_width/2.))
+        +(ladder_clothest_approch+cos(phirot)*2*(active_silicon_thickness+flex_cable_thickness+metal_traces_thickness))/sin(phirot));
+    
     if (LayerId==0||LayerId==2||LayerId==4)  {  //------------------------------------------------------------------------
        
       for (double ladder_loop=0;ladder_loop<nb_ladder;ladder_loop++) {
@@ -581,7 +587,6 @@ static Ref_t create_element(Detector& theDetector, xml_h e, SensitiveDetector se
       beryllium_ladder_block_length2 = beryllium_ladder_block_length + (shell_half_z - (end_electronics_half_z *3.* end_ladd_electronics_option)-ladder_length);
       
       for (double AnnulusBlock_loop=0;AnnulusBlock_loop<nb_ladder;AnnulusBlock_loop++) {
-	
 	Box BerylliumAnnulusBlockSolid( ladder_width, beryllium_ladder_block_length2/2., beryllium_ladder_block_thickness);
 	
 	//**fg: need to create unique string name per Volume object
@@ -1200,7 +1205,9 @@ static Ref_t create_element(Detector& theDetector, xml_h e, SensitiveDetector se
     }
     //Adjusted by Thorben Quast to provide consistency with CLIC while drawing for CED
     //Please check as the prefactor is simply chosen for the geometry to match the hits
-    thisLayer.offsetSensitive    = 0.5*active_offset_phi ;
+    //thisLayer.offsetSensitive    = 0.5*active_offset_phi ;
+    //without CED as first step @CepC, by fucd
+    thisLayer.offsetSensitive    = active_offset_phi ;
     thisLayer.thicknessSensitive = active_silicon_thickness ;
     thisLayer.zHalfSensitive    = ladder_length ;