diff --git a/contrib/extractor/System.cpp b/contrib/extractor/System.cpp
index 3a9650c2c..d1af9e12b 100644
--- a/contrib/extractor/System.cpp
+++ b/contrib/extractor/System.cpp
@@ -60,6 +60,7 @@ enum Extract
 // Select data for extract
 int   CONF_extract = EXTRACT_MAP | EXTRACT_DBC;
 // This option allow limit minimum height to some value (Allow save some memory)
+// see contrib/mmap/src/Tilebuilder.h, INVALID_MAP_LIQ_HEIGHT
 bool  CONF_allow_height_limit = true;
 float CONF_use_minHeight = -500.0f;
 
@@ -292,6 +293,8 @@ struct map_fileheader
     uint32 heightMapSize;
     uint32 liquidMapOffset;
     uint32 liquidMapSize;
+    uint32 holesOffset;
+    uint32 holesSize;
 };
 
 #define MAP_AREA_NO_AREA      0x0001
@@ -795,8 +798,8 @@ bool ConvertADT(char *filename, char *filename2, int cell_y, int cell_x, uint32
         liquidHeader.liquidType = 0;
         liquidHeader.offsetX = minX;
         liquidHeader.offsetY = minY;
-        liquidHeader.width   = maxX - minX + 1;
-        liquidHeader.height  = maxY - minY + 1;
+        liquidHeader.width   = maxX - minX + 1 + 1;
+        liquidHeader.height  = maxY - minY + 1 + 1;
         liquidHeader.liquidLevel = minHeight;
 
         if (maxHeight == minHeight)
@@ -818,6 +821,28 @@ bool ConvertADT(char *filename, char *filename2, int cell_y, int cell_x, uint32
             map.liquidMapSize += sizeof(float)*liquidHeader.width*liquidHeader.height;
     }
 
+    // map hole info
+    uint16 holes[ADT_CELLS_PER_GRID][ADT_CELLS_PER_GRID];
+
+    if(map.liquidMapOffset)
+        map.holesOffset = map.liquidMapOffset + map.liquidMapSize;
+    else
+        map.holesOffset = map.heightMapOffset + map.heightMapSize;
+
+    map.holesSize = sizeof(holes);
+    memset(holes, 0, map.holesSize);
+
+    for(int i = 0; i < ADT_CELLS_PER_GRID; ++i)
+    {
+        for(int j = 0; j < ADT_CELLS_PER_GRID; ++j)
+        {
+            adt_MCNK * cell = cells->getMCNK(i,j);
+            if(!cell)
+                continue;
+            holes[i][j] = cell->holes;
+        }
+    }
+
     // Ok all data prepared - store it
     FILE *output=fopen(filename2, "wb");
     if(!output)
@@ -864,6 +889,10 @@ bool ConvertADT(char *filename, char *filename2, int cell_y, int cell_x, uint32
                 fwrite(&liquid_height[y+liquidHeader.offsetY][liquidHeader.offsetX], sizeof(float), liquidHeader.width, output);
         }
     }
+
+    // store hole data
+    fwrite(holes, map.holesSize, 1, output);
+
     fclose(output);
 
     return true;
diff --git a/contrib/extractor/loadlib/adt.h b/contrib/extractor/loadlib/adt.h
index 729412ada..9c9167376 100644
--- a/contrib/extractor/loadlib/adt.h
+++ b/contrib/extractor/loadlib/adt.h
@@ -93,7 +93,8 @@ public:
     uint32 sizeMCSH;
     uint32 areaid;
     uint32 nMapObjRefs;
-    uint32 holes;
+    uint16 holes;           // locations where models pierce the heightmap
+    uint16 pad;
     uint16 s[2];
     uint32 data1;
     uint32 data2;
@@ -286,4 +287,6 @@ public:
     adt_MHDR *a_grid;
 };
 
+bool isHole(int holes, int i, int j);
+
 #endif
diff --git a/src/game/GridMap.h b/src/game/GridMap.h
index 278329794..12693ad21 100644
--- a/src/game/GridMap.h
+++ b/src/game/GridMap.h
@@ -48,6 +48,8 @@ struct GridMapFileHeader
     uint32 heightMapSize;
     uint32 liquidMapOffset;
     uint32 liquidMapSize;
+    uint32 holesOffset;
+    uint32 holesSize;
 };
 
 #define MAP_AREA_NO_AREA      0x0001
diff --git a/src/shared/revision_nr.h b/src/shared/revision_nr.h
index c64d72ef8..a868aab59 100644
--- a/src/shared/revision_nr.h
+++ b/src/shared/revision_nr.h
@@ -1,4 +1,4 @@
 #ifndef __REVISION_NR_H__
 #define __REVISION_NR_H__
- #define REVISION_NR "11903"
+ #define REVISION_NR "11904"
 #endif // __REVISION_NR_H__