diff --git a/pom.xml b/pom.xml
index f08170a..700a76a 100644
--- a/pom.xml
+++ b/pom.xml
@@ -4,7 +4,7 @@
     <groupId>com.geosiris</groupId>
     <artifactId>energyml-utils</artifactId>
     <name>${project.groupId}:${project.artifactId}</name>
-    <version>1.0.10</version>
+    <version>1.0.11</version>
     <organization>
         <name>Geosiris</name>
         <url>http://www.geosiris.com</url>
diff --git a/src/main/java/com/geosiris/energyml/data/Mesh.java b/src/main/java/com/geosiris/energyml/data/Mesh.java
index c64884d..5270dc6 100644
--- a/src/main/java/com/geosiris/energyml/data/Mesh.java
+++ b/src/main/java/com/geosiris/energyml/data/Mesh.java
@@ -18,17 +18,22 @@
 import com.geosiris.energyml.exception.NotImplementedException;
 import com.geosiris.energyml.exception.ObjectNotFoundNotError;
 import com.geosiris.energyml.pkg.EPCFile;
+import com.geosiris.energyml.pkg.EpcHdf5FileManager;
 import com.geosiris.energyml.utils.EnergymlWorkspace;
 import com.geosiris.energyml.utils.ObjectController;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 
+import java.io.FileOutputStream;
+import java.io.IOException;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 import java.util.*;
 import java.util.stream.Collectors;
 import java.util.stream.IntStream;
 
+import static com.geosiris.energyml.data.SurfaceMesh.exportObj;
+import static com.geosiris.energyml.data.SurfaceMesh.exportOff;
 import static com.geosiris.energyml.utils.EnergymlWorkspaceHelper.*;
 import static com.geosiris.energyml.utils.ObjectController.searchAttributeMatchingNameWithPath;
 
@@ -318,7 +323,7 @@ public static List<GridedPointSetMesh> readGrid2dRepresentationPoints(Object ene
         return meshes;
     }
 
-    public static List<SurfaceMesh> readTriangulatedSetRepresentation (Object energymlObject, EnergymlWorkspace
+    public static List<SurfaceMesh> readTriangulatedSetRepresentation(Object energymlObject, EnergymlWorkspace
             workspace) throws NotImplementedException, InvocationTargetException, IllegalAccessException {
         List<SurfaceMesh> meshes = new ArrayList<>();
         try {
@@ -359,7 +364,7 @@ public static List<SurfaceMesh> readTriangulatedSetRepresentation (Object energy
                             pointList.addAll(((List<List<?>>) pl).stream()
                                     .map(l -> l.stream().map(v -> ((Number) v).doubleValue()).collect(Collectors.toList())).collect(Collectors.toList()));
                         } else { // pl given flat
-                            for (int i = 0; i < pl.size() - 2; i++) {
+                            for (int i = 0; i < pl.size() - 2; i+=3) {
                                 pointList.add(new ArrayList<>(List.of(
                                         ((Number) pl.get(i)).doubleValue(),
                                         ((Number) pl.get(i + 1)).doubleValue(),
@@ -382,7 +387,7 @@ public static List<SurfaceMesh> readTriangulatedSetRepresentation (Object energy
                         trianglesList_obj.addAll(((List<List<?>>)indices).stream()
                             .map(l -> l.stream().map(v -> ((Number)v).longValue()).collect(Collectors.toList())).collect(Collectors.toList()));
                     }else{ // indices given flat
-                        for(int i=0; i<indices.size()-2; i++){
+                        for(int i=0; i<indices.size()-2; i+=3){
                             trianglesList_obj.add(new ArrayList<>(List.of(
                                     ((Number)indices.get(i)).longValue(),
                                     ((Number)indices.get(i+1)).longValue(),
@@ -417,4 +422,5 @@ public static List<SurfaceMesh> readTriangulatedSetRepresentation (Object energy
 
         return meshes;
     }
+
 }
\ No newline at end of file
diff --git a/src/main/java/com/geosiris/energyml/data/SurfaceMesh.java b/src/main/java/com/geosiris/energyml/data/SurfaceMesh.java
index 4c0566e..3c8fd56 100644
--- a/src/main/java/com/geosiris/energyml/data/SurfaceMesh.java
+++ b/src/main/java/com/geosiris/energyml/data/SurfaceMesh.java
@@ -16,9 +16,13 @@
 package com.geosiris.energyml.data;
 
 import com.geosiris.energyml.exception.NotImplementedException;
+import com.geosiris.energyml.pkg.EpcHdf5FileManager;
 
+import java.io.ByteArrayOutputStream;
+import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
+import java.lang.reflect.InvocationTargetException;
 import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.List;
@@ -110,12 +114,13 @@ public static void exportObjElt(
                 );
                 if (colors != null && colors.size() > cpt && colors.get(cpt) != null && !colors.get(cpt).isEmpty())
                 {
-                    pointPart.write(String.format("%s",
+                    facePart.write(String.format("%s",
                         colors.get(cpt).stream().map(String::valueOf).collect(Collectors.joining(" "))).getBytes(StandardCharsets.UTF_8)
                     );
                 }
-                pointPart.write("\n".getBytes(StandardCharsets.UTF_8));
+                facePart.write("\n".getBytes(StandardCharsets.UTF_8));
             }
+            cpt++;
         }
     }
 
@@ -136,29 +141,34 @@ public static void exportOffElt(
             Long pointOffset,
             List<List<Integer>> colors
             ) throws IOException {
-        Long offsetObj = 1L;  // OBJ point indices starts at 1 not 0
         for(var p: points) {
             if (!p.isEmpty())
                 pointPart.write(String.format("%s\n",
                         p.stream().map(String::valueOf).collect(Collectors.joining(" "))).getBytes(StandardCharsets.UTF_8)
                 );
         }
-        // cpt = 0
+        int cpt = 0;
         for(var face: indices) {
-            if(!indices.isEmpty())
+            if(!indices.isEmpty()) {
                 facePart.write(
-                        String.format("%s\n",
-                                        face.stream().map(x -> String.valueOf(x + pointOffset + offsetObj)).collect(Collectors.joining(" ")))
+                        String.format("%d %s %s\n",
+                                        face.size(),
+                                        face.stream().map(x -> String.valueOf(x + pointOffset)).collect(Collectors.joining(" ")),
+                                        cpt >= colors.size() ? "" : colors.get(cpt).stream().map(String::valueOf).collect(Collectors.joining(" "))
+                                )
                                 .getBytes(
                                         StandardCharsets.UTF_8)
                 );
+            }
+            cpt++;
         }
     }
 
     public static void exportObj(
             List<AbstractMesh> meshList,
             OutputStream out,
-            String objName
+            String objName,
+            Boolean useOffset
             ) throws IOException {
         out.write("# Generated by energyml-utils a Geosiris python module\n\n".getBytes(StandardCharsets.UTF_8));
         if(objName != null){
@@ -173,7 +183,7 @@ public static void exportObj(
                     out,
                     (List<List<Double>>) m.pointList,
                     m.getEdgeIndices(),
-                    pointOffset,
+                    useOffset ? pointOffset : 0,
                     new ArrayList<>(),
                     m instanceof PolylineSetMesh ? "l" : "f"
             );
@@ -181,4 +191,37 @@ public static void exportObj(
             out.write("\n".getBytes(StandardCharsets.UTF_8));
         }
     }
+
+    public static void exportOff(
+            List<AbstractMesh> meshList,
+            OutputStream out,
+            String objName,
+            Boolean useOffset
+            ) throws IOException {
+        out.write("OFF\n# Generated by energyml-utils a Geosiris python module\n\n".getBytes(StandardCharsets.UTF_8));
+        out.write(String.format("%d %d %d\n",
+                meshList.stream().map(AbstractMesh::getNbPoints).reduce(0L, Long::sum),
+                meshList.stream().map(AbstractMesh::getNbFaces).reduce(0L, Long::sum),
+                meshList.stream().map(AbstractMesh::getNbEdge).reduce(0L, Long::sum)
+                ).getBytes(StandardCharsets.UTF_8)
+        );
+
+        ByteArrayOutputStream out_i = new ByteArrayOutputStream();
+
+        Long pointOffset = 0L;
+        for(var m: meshList){
+            exportOffElt(
+                    out,
+                    out_i,
+                    (List<List<Double>>) m.pointList,
+                    m.getEdgeIndices(),
+                    useOffset ? pointOffset : 0,
+                    new ArrayList<>()
+            );
+            pointOffset += m.pointList.size();
+            out.write("\n".getBytes(StandardCharsets.UTF_8));
+        }
+
+        out_i.writeTo(out);
+    }
 }