diff --git a/src/surfMesh/Make/files b/src/surfMesh/Make/files
index d6e808f6f0..19c5eee8b5 100644
--- a/src/surfMesh/Make/files
+++ b/src/surfMesh/Make/files
@@ -25,6 +25,7 @@ $(surfaceFormats)/starcd/STARCDsurfaceFormatRunTime.C
 $(surfaceFormats)/stl/STLsurfaceFormatCore.C
 $(surfaceFormats)/stl/STLsurfaceFormatRunTime.C
 $(surfaceFormats)/stl/STLsurfaceFormatASCII.L
+$(surfaceFormats)/tri/TRIsurfaceFormatCore.C
 $(surfaceFormats)/tri/TRIsurfaceFormatRunTime.C
 $(surfaceFormats)/vtk/VTKsurfaceFormatCore.C
 $(surfaceFormats)/vtk/VTKsurfaceFormatRunTime.C
diff --git a/src/surfMesh/MeshedSurface/MeshedSurface.C b/src/surfMesh/MeshedSurface/MeshedSurface.C
index cb4f795bc6..205ed3a981 100644
--- a/src/surfMesh/MeshedSurface/MeshedSurface.C
+++ b/src/surfMesh/MeshedSurface/MeshedSurface.C
@@ -758,6 +758,54 @@ void Foam::MeshedSurface<Face>::addPatches
 }
 
 
+template<class Face>
+void Foam::MeshedSurface<Face>::addPatches
+(
+    const UList<word>& names,
+    const UList<label>& sizes
+)
+{
+    patches_.setSize(sizes.size());
+
+    label start = 0;
+    forAll(patches_, patchI)
+    {
+        patches_[patchI] = surfGroup
+        (
+            names[patchI],
+            sizes[patchI],
+            start,
+            patchI
+        );
+
+        start += sizes[patchI];
+    }
+}
+
+template<class Face>
+void Foam::MeshedSurface<Face>::addPatches
+(
+    const UList<label>& sizes
+)
+{
+    patches_.setSize(sizes.size());
+
+    label start = 0;
+    forAll(patches_, patchI)
+    {
+        patches_[patchI] = surfGroup
+        (
+            word("patch") + ::Foam::name(patchI),
+            sizes[patchI],
+            start,
+            patchI
+        );
+
+        start += sizes[patchI];
+    }
+}
+
+
 template<class Face>
 void Foam::MeshedSurface<Face>::transfer
 (
diff --git a/src/surfMesh/MeshedSurface/MeshedSurface.H b/src/surfMesh/MeshedSurface/MeshedSurface.H
index e6665a2845..ed8dce123f 100644
--- a/src/surfMesh/MeshedSurface/MeshedSurface.H
+++ b/src/surfMesh/MeshedSurface/MeshedSurface.H
@@ -276,6 +276,9 @@ public:
         }
 
         void addPatches(const UList<surfGroup>&);
+    
+        void addPatches(const UList<word>& names, const UList<label>& sizes);
+        void addPatches(const UList<label>& sizes);
 
 
     // Edit
diff --git a/src/surfMesh/surfaceFormats/ac3d/AC3DsurfaceFormat.C b/src/surfMesh/surfaceFormats/ac3d/AC3DsurfaceFormat.C
index 7e5a8068c7..82026e8acf 100644
--- a/src/surfMesh/surfaceFormats/ac3d/AC3DsurfaceFormat.C
+++ b/src/surfMesh/surfaceFormats/ac3d/AC3DsurfaceFormat.C
@@ -106,12 +106,9 @@ bool Foam::fileFormats::AC3DsurfaceFormat<Face>::read
     // Start of vertices for object/patch
     label patchVertOffset = 0;
 
-    DynamicList<point> pointLst;
-    DynamicList<Face>  faceLst;
-    DynamicList<label> regionLst;
-
-    // patchId => patchName
-    Map<word> regionNames;
+    DynamicList<point> dynPoints;
+    DynamicList<Face>  dynFaces;
+    List<label> sizes(nPatches, 0);
 
     for (label patchI = 0; patchI < nPatches; ++patchI)
     {
@@ -193,7 +190,7 @@ bool Foam::fileFormats::AC3DsurfaceFormat<Face>::read
                         >> pt.x() >> pt.y() >> pt.z();
 
                     // Offset with current translation vector
-                    pointLst.append(location + pt);
+                    dynPoints.append(location + pt);
                 }
             }
             else if (cmd == "numsurf")
@@ -238,14 +235,14 @@ bool Foam::fileFormats::AC3DsurfaceFormat<Face>::read
                             fTri[1] = verts[fp1];
                             fTri[2] = verts[fp2];
 
-                            faceLst.append(fTri);
-                            regionLst.append(patchI);
+                            dynFaces.append(fTri);
+                            sizes[patchI]++;
                         }
                     }
                     else
                     {
-                        faceLst.append(Face(f));
-                        regionLst.append(patchI);
+                        dynFaces.append(Face(f));
+                        sizes[patchI]++;
                     }
                 }
 
@@ -271,23 +268,79 @@ bool Foam::fileFormats::AC3DsurfaceFormat<Face>::read
                 }
 
                 // Done reading current patch
-                regionNames.insert(patchI, patchName);
                 break;
             }
         }
     }
 
     // transfer to normal lists
-    this->storedPoints().transfer(pointLst);
-    this->storedFaces().transfer(faceLst);
-    this->storedRegions().transfer(regionLst);
+    this->storedPoints().transfer(dynPoints);
+    this->storedFaces().transfer(dynFaces);
 
-    this->setPatches(regionNames);
+    this->addPatches(sizes);
     this->stitchFaces(SMALL);
     return true;
 }
 
 
+template<class Face>
+void Foam::fileFormats::AC3DsurfaceFormat<Face>::write
+(
+    Ostream& os,
+    const MeshedSurface<Face>& surf
+)
+{
+    const pointField& pointLst = surf.points();
+    const List<Face>& faceLst = surf.faces();
+    const List<surfGroup>& patchLst = surf.patches();
+
+    writeHeader(os, patchLst);
+
+    forAll(patchLst, patchI)
+    {
+        const surfGroup& p = patchLst[patchI];
+
+        os  << "OBJECT poly" << nl
+            << "name \"" << p.name() << '"' << endl;
+
+        // Temporary PrimitivePatch to calculate compact points & faces
+        // use 'UList' to avoid allocations!
+        PrimitivePatch<Face, UList, const pointField&> patch
+        (
+            faceLst,
+            pointLst
+        );
+
+        os << "numvert " << patch.nPoints() << endl;
+
+        forAll(patch.localPoints(), ptI)
+        {
+            const point& pt = patch.localPoints()[ptI];
+
+            os << pt.x() << ' ' << pt.y() << ' ' << pt.z() << endl;
+        }
+
+        os << "numsurf " << patch.localFaces().size() << endl;
+
+        forAll(patch.localFaces(), faceI)
+        {
+            const Face& f = patch.localFaces()[faceI];
+
+            os  << "SURF 0x20" << nl          // polygon
+                << "mat " << patchI << nl
+                << "refs " << f.size() << nl;
+
+            forAll(f, fp)
+            {
+                os << f[fp] << " 0 0" << nl;
+            }
+        }
+
+        os << "kids 0" << endl;
+    }
+}
+
+
 template<class Face>
 void Foam::fileFormats::AC3DsurfaceFormat<Face>::write
 (
@@ -350,61 +403,4 @@ void Foam::fileFormats::AC3DsurfaceFormat<Face>::write
 }
 
 
-template<class Face>
-void Foam::fileFormats::AC3DsurfaceFormat<Face>::write
-(
-    Ostream& os,
-    const MeshedSurface<Face>& surf
-)
-{
-    const pointField& pointLst = surf.points();
-    const List<Face>& faceLst = surf.faces();
-    const List<surfGroup>& patchLst = surf.patches();
-
-    writeHeader(os, patchLst);
-
-    forAll(patchLst, patchI)
-    {
-        const surfGroup& p = patchLst[patchI];
-
-        os  << "OBJECT poly" << nl
-            << "name \"" << p.name() << '"' << endl;
-
-        // Temporary PrimitivePatch to calculate compact points & faces
-        // use 'UList' to avoid allocations!
-        PrimitivePatch<Face, UList, const pointField&> patch
-        (
-            faceLst,
-            pointLst
-        );
-
-        os << "numvert " << patch.nPoints() << endl;
-
-        forAll(patch.localPoints(), ptI)
-        {
-            const point& pt = patch.localPoints()[ptI];
-
-            os << pt.x() << ' ' << pt.y() << ' ' << pt.z() << endl;
-        }
-
-        os << "numsurf " << patch.localFaces().size() << endl;
-
-        forAll(patch.localFaces(), faceI)
-        {
-            const Face& f = patch.localFaces()[faceI];
-
-            os  << "SURF 0x20" << nl          // polygon
-                << "mat " << patchI << nl
-                << "refs " << f.size() << nl;
-
-            forAll(f, fp)
-            {
-                os << f[fp] << " 0 0" << nl;
-            }
-        }
-
-        os << "kids 0" << endl;
-    }
-}
-
 // ************************************************************************* //
diff --git a/src/surfMesh/surfaceFormats/ac3d/AC3DsurfaceFormat.H b/src/surfMesh/surfaceFormats/ac3d/AC3DsurfaceFormat.H
index b95dfd7e20..1388445010 100644
--- a/src/surfMesh/surfaceFormats/ac3d/AC3DsurfaceFormat.H
+++ b/src/surfMesh/surfaceFormats/ac3d/AC3DsurfaceFormat.H
@@ -31,9 +31,7 @@ Description
     http://www.inivis.com/ac3d/man/ac3dfileformat.html
 
 Note
-   Since the faces are already organized as patches, the reader could be
-   optimized for this, but at expense of losing a common reading approach.
-
+   The faces are already organized as patches.
    The output is always sorted by regions.
 
 SourceFiles
@@ -64,7 +62,7 @@ namespace fileFormats
 template<class Face>
 class AC3DsurfaceFormat
 :
-    public UnsortedMeshedSurface<Face>,
+    public MeshedSurface<Face>,
     public AC3DsurfaceFormatCore
 {
     // Private Member Functions
@@ -85,12 +83,12 @@ public:
     // Selectors
 
         //- Read file and return surface
-        static autoPtr<UnsortedMeshedSurface<Face> > New
+        static autoPtr<MeshedSurface<Face> > New
         (
             const fileName& fName
         )
         {
-            return autoPtr<UnsortedMeshedSurface<Face> >
+            return autoPtr<MeshedSurface<Face> >
             (
                 new AC3DsurfaceFormat<Face>(fName)
             );
diff --git a/src/surfMesh/surfaceFormats/ac3d/AC3DsurfaceFormatRunTime.C b/src/surfMesh/surfaceFormats/ac3d/AC3DsurfaceFormatRunTime.C
index 6e2ea87e91..b19709ffbb 100644
--- a/src/surfMesh/surfaceFormats/ac3d/AC3DsurfaceFormatRunTime.C
+++ b/src/surfMesh/surfaceFormats/ac3d/AC3DsurfaceFormatRunTime.C
@@ -38,7 +38,7 @@ namespace fileFormats
 
 addNamedTemplatedToRunTimeSelectionTable
 (
-    UnsortedMeshedSurface,
+    MeshedSurface,
     AC3DsurfaceFormat,
     face,
     fileExtension,
@@ -46,7 +46,7 @@ addNamedTemplatedToRunTimeSelectionTable
 );
 addNamedTemplatedToRunTimeSelectionTable
 (
-    UnsortedMeshedSurface,
+    MeshedSurface,
     AC3DsurfaceFormat,
     triFace,
     fileExtension,
diff --git a/src/surfMesh/surfaceFormats/stl/STLsurfaceFormat.C b/src/surfMesh/surfaceFormats/stl/STLsurfaceFormat.C
index 5367e130a6..6fbc43b78b 100644
--- a/src/surfMesh/surfaceFormats/stl/STLsurfaceFormat.C
+++ b/src/surfMesh/surfaceFormats/stl/STLsurfaceFormat.C
@@ -94,6 +94,36 @@ inline void Foam::fileFormats::STLsurfaceFormat<Face>::writeShell
 }
 
 
+// write sorted:
+template<class Face>
+void Foam::fileFormats::STLsurfaceFormat<Face>::writeASCII
+(
+    Ostream& os,
+    const MeshedSurface<Face>& surf
+)
+{
+    const pointField& pointLst = surf.points();
+    const List<Face>& faceLst = surf.faces();
+    const List<surfGroup>& patchLst = surf.patches();
+    const vectorField& normLst = surf.faceNormals();
+
+    label faceIndex = 0;
+    forAll(patchLst, patchI)
+    {
+        // Print all faces belonging to this region
+        const surfGroup& patch = patchLst[patchI];
+
+        os << "solid " << patch.name() << endl;
+        forAll(patch, patchFaceI)
+        {
+            const label faceI = faceIndex++;
+            writeShell(os, pointLst, faceLst[faceI], normLst[faceI]);
+        }
+        os << "endsolid " << patch.name() << endl;
+    }
+}
+
+
 // write sorted:
 template<class Face>
 void Foam::fileFormats::STLsurfaceFormat<Face>::writeASCII
@@ -136,86 +166,10 @@ void Foam::fileFormats::STLsurfaceFormat<Face>::writeASCII
             os << "endsolid " << patch.name() << endl;
         }
    }
-
 }
 
 
 
-// write sorted:
-template<class Face>
-void Foam::fileFormats::STLsurfaceFormat<Face>::writeASCII
-(
-    Ostream& os,
-    const MeshedSurface<Face>& surf
-)
-{
-    const pointField& pointLst = surf.points();
-    const List<Face>& faceLst = surf.faces();
-    const List<surfGroup>& patchLst = surf.patches();
-    const vectorField& normLst = surf.faceNormals();
-
-    label faceIndex = 0;
-    forAll(patchLst, patchI)
-    {
-        // Print all faces belonging to this region
-        const surfGroup& patch = patchLst[patchI];
-
-        os << "solid " << patch.name() << endl;
-        forAll(patch, patchFaceI)
-        {
-            const label faceI = faceIndex++;
-            writeShell(os, pointLst, faceLst[faceI], normLst[faceI]);
-        }
-        os << "endsolid " << patch.name() << endl;
-    }
-}
-
-
-// write unsorted:
-template<class Face>
-void Foam::fileFormats::STLsurfaceFormat<Face>::writeBINARY
-(
-    ostream& os,
-    const UnsortedMeshedSurface<Face>& surf
-)
-{
-    const pointField& pointLst = surf.points();
-    const List<Face>&  faceLst = surf.faces();
-    const List<label>& regionLst = surf.regions();
-    const vectorField& normLst = surf.faceNormals();
-
-    unsigned int nTris = 0;
-    if (surf.isTri())
-    {
-        nTris = faceLst.size();
-    }
-    else
-    {
-        // count triangles for on-the-fly triangulation
-        forAll(faceLst, faceI)
-        {
-            nTris += faceLst[faceI].size() - 2;
-        }
-    }
-
-    // Write the STL header
-    STLsurfaceFormatCore::writeHeaderBINARY(os, nTris);
-
-    // always write unsorted
-    forAll(faceLst, faceI)
-    {
-        writeShell
-        (
-            os,
-            pointLst,
-            faceLst[faceI],
-            normLst[faceI],
-            regionLst[faceI]
-        );
-    }
-}
-
-
 template<class Face>
 void Foam::fileFormats::STLsurfaceFormat<Face>::writeBINARY
 (
@@ -265,6 +219,51 @@ void Foam::fileFormats::STLsurfaceFormat<Face>::writeBINARY
 }
 
 
+// write unsorted:
+template<class Face>
+void Foam::fileFormats::STLsurfaceFormat<Face>::writeBINARY
+(
+    ostream& os,
+    const UnsortedMeshedSurface<Face>& surf
+)
+{
+    const pointField& pointLst = surf.points();
+    const List<Face>&  faceLst = surf.faces();
+    const List<label>& regionLst = surf.regions();
+    const vectorField& normLst = surf.faceNormals();
+
+    unsigned int nTris = 0;
+    if (surf.isTri())
+    {
+        nTris = faceLst.size();
+    }
+    else
+    {
+        // count triangles for on-the-fly triangulation
+        forAll(faceLst, faceI)
+        {
+            nTris += faceLst[faceI].size() - 2;
+        }
+    }
+
+    // Write the STL header
+    STLsurfaceFormatCore::writeHeaderBINARY(os, nTris);
+
+    // always write unsorted
+    forAll(faceLst, faceI)
+    {
+        writeShell
+        (
+            os,
+            pointLst,
+            faceLst[faceI],
+            normLst[faceI],
+            regionLst[faceI]
+        );
+    }
+}
+
+
 // * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
 
 template<class Face>
@@ -293,67 +292,51 @@ bool Foam::fileFormats::STLsurfaceFormat<Face>::read
     // transfer points
     this->storedPoints().transfer(reader.points());
 
-    // get the original region information
+    // retrieve the original region information
     List<word>  names(xferMove(reader.names()));
-    List<label> unsortedRegions(xferMove(reader.regions()));
+    List<label> sizes(xferMove(reader.sizes()));
+    List<label> regions(xferMove(reader.regions()));
 
-    // and determine the sorted order:
-    // avoid SortableList since we discard the main list anyhow
-    List<label> faceMap;
-    sortedOrder(unsortedRegions, faceMap);
+    // generate the (sorted) faces
+    List<Face> faceLst(regions.size());
 
-    // generate the sorted faces and sorted regions:
-    List<Face> faceLst(faceMap.size());
-
-    DynamicList<label> dynPatchSizes;
-    label prevRegion = -1;
-    label regionSize = 0;
-
-    forAll(faceMap, faceI)
+    if (reader.sorted())
     {
-        const label startPt = 3*faceMap[faceI];
-        const label regionI = unsortedRegions[faceMap[faceI]];
-
-        faceLst[faceI] = triFace(startPt, startPt+1, startPt+2);
-
-        if (prevRegion != regionI)
+        // already sorted - generate directly
+        forAll(faceLst, faceI)
         {
-            if (regionSize)
-            {
-                dynPatchSizes.append(regionSize);
-            }
-            prevRegion = regionI;
-            regionSize = 0;
+            const label startPt = 3*faceI;
+            faceLst[faceI] = triFace(startPt, startPt+1, startPt+2);
         }
-        regionSize++;
     }
-
-    if (regionSize)
+    else
     {
-        dynPatchSizes.append(regionSize);
+        // unsorted - determine the sorted order:
+        // avoid SortableList since we discard the main list anyhow
+        List<label> faceMap;
+        sortedOrder(regions, faceMap);
+
+        // generate sorted faces
+        forAll(faceMap, faceI)
+        {
+            const label startPt = 3*faceMap[faceI];
+            faceLst[faceI] = triFace(startPt, startPt+1, startPt+2);
+        }
     }
+    regions.clear();
 
     // transfer:
     this->storedFaces().transfer(faceLst);
-    unsortedRegions.clear();
-    faceMap.clear();
 
-    label start = 0;
-    surfGroupList newPatches(dynPatchSizes.size());
-    forAll(newPatches, patchI)
+    if (names.size())
     {
-        newPatches[patchI] = surfGroup
-        (
-            names[patchI],
-            dynPatchSizes[patchI],
-            start,
-            patchI
-        );
-
-        start += dynPatchSizes[patchI];
+        this->addPatches(names, sizes);
+    }
+    else
+    {
+        this->addPatches(names, sizes);
     }
 
-    this->addPatches(newPatches);
     this->stitchFaces(SMALL);
     return true;
 }
diff --git a/src/surfMesh/surfaceFormats/stl/STLsurfaceFormatASCII.L b/src/surfMesh/surfaceFormats/stl/STLsurfaceFormatASCII.L
index e01b96fbb8..4737137b9c 100644
--- a/src/surfMesh/surfaceFormats/stl/STLsurfaceFormatASCII.L
+++ b/src/surfMesh/surfaceFormats/stl/STLsurfaceFormatASCII.L
@@ -72,6 +72,7 @@ class STLASCIILexer
 {
     // Private data
 
+        bool  sorted_;
         label groupID_;      // current region
         label lineNo_;
         word  startError_;
@@ -79,7 +80,8 @@ class STLASCIILexer
         DynamicList<point> points_;
         DynamicList<label> facets_;
         DynamicList<word>  names_;
-        HashTable<label>   nameIndex_;
+        DynamicList<label> sizes_;
+        HashTable<label>   lookup_;
 
 public:
 
@@ -96,6 +98,12 @@ public:
 
     // Access
 
+        //- Do all the solid groups appear in order
+        bool sorted() const
+        {
+            return sorted_;
+        }
+
         //- A list of points corresponding to a pointField
         DynamicList<point>& points()
         {
@@ -114,12 +122,19 @@ public:
         {
             return names_;
         }
+
+        //- region sizes
+        DynamicList<label>& sizes()
+        {
+            return sizes_;
+        }
 };
 
 
 STLASCIILexer::STLASCIILexer(istream* is, const label approxNpoints)
 :
     yyFlexLexer(is),
+    sorted_(true),
     groupID_(-1),
     lineNo_(1),
     points_(approxNpoints),
@@ -237,16 +252,22 @@ endsolid              {space}("endsolid"|"ENDSOLID")({some_space}{word})*
 <readSolidName>{string} {
         word name(Foam::string::validate<word>(YYText()));
 
-        HashTable<label>::const_iterator fnd = nameIndex_.find(name);
-        if (fnd != nameIndex_.end())
+        HashTable<label>::const_iterator fnd = lookup_.find(name);
+        if (fnd != lookup_.end())
         {
+            if (groupID_ != fnd())
+            {
+                // group appeared out of order
+                sorted_ = false;
+            }
             groupID_ = fnd();
         }
         else
         {
-            groupID_ = names_.size();
+            groupID_ = sizes_.size();
+            lookup_.insert(name, groupID_);
             names_.append(name);
-            nameIndex_.insert(name, groupID_);
+            sizes_.append(0);
         }
         BEGIN(INITIAL);
     }
@@ -254,16 +275,22 @@ endsolid              {space}("endsolid"|"ENDSOLID")({some_space}{word})*
 <readSolidName>{space}\n {
         word name("solid");
 
-        HashTable<label>::const_iterator fnd = nameIndex_.find(name);
-        if (fnd != nameIndex_.end())
+        HashTable<label>::const_iterator fnd = lookup_.find(name);
+        if (fnd != lookup_.end())
         {
+            if (groupID_ != fnd())
+            {
+                // group appeared out of order
+                sorted_ = false;
+            }
             groupID_ = fnd();
         }
         else
         {
-            groupID_ = names_.size();
+            groupID_ = sizes_.size();
+            lookup_.insert(name, groupID_);
             names_.append(name);
-            nameIndex_.insert(name, groupID_);
+            sizes_.append(0);
         }
 
         lineNo_++;
@@ -328,6 +355,7 @@ endsolid              {space}("endsolid"|"ENDSOLID")({some_space}{word})*
 
 <readFacet>{endfacet} {
         facets_.append(groupID_);
+        sizes_[groupID_]++;
         BEGIN(INITIAL);
     }
 
@@ -380,17 +408,18 @@ bool Foam::fileFormats::STLsurfaceFormatCore::readASCII
     const off_t fileSize
 )
 {
-    binary_ = false;
-
     // Create the lexer with the approximate number of vertices in the STL
     // from the file size
     STLASCIILexer lexer(&ifs.stdStream(), fileSize/400);
     while (lexer.lex() != 0) {}
 
+    sorted_ = lexer.sorted();
+
     // transfer to normal lists
     points_.transfer(lexer.points());
     regions_.transfer(lexer.facets());
     names_.transfer(lexer.names());
+    sizes_.transfer(lexer.sizes());
 
     return true;
 }
diff --git a/src/surfMesh/surfaceFormats/stl/STLsurfaceFormatCore.C b/src/surfMesh/surfaceFormats/stl/STLsurfaceFormatCore.C
index 7aa29789e2..d6a3ca3fbd 100644
--- a/src/surfMesh/surfaceFormats/stl/STLsurfaceFormatCore.C
+++ b/src/surfMesh/surfaceFormats/stl/STLsurfaceFormatCore.C
@@ -92,7 +92,7 @@ bool Foam::fileFormats::STLsurfaceFormatCore::readBINARY
     const off_t fileSize
 )
 {
-    binary_ = true;
+    sorted_ = true;
     istream& is = ifs.stdStream();
 
     // Read the STL header
@@ -144,10 +144,11 @@ bool Foam::fileFormats::STLsurfaceFormatCore::readBINARY
     points_.setSize(3*nTris);
     regions_.setSize(nTris);
 
-    Map<label> regionToPatch;
-    DynamicList<word> dynNames;
+    Map<label> lookup;
+    DynamicList<label> dynSizes;
 
     label ptI = 0;
+    label regionI = -1;
     forAll(regions_, faceI)
     {
         // Read an STL triangle
@@ -161,20 +162,25 @@ bool Foam::fileFormats::STLsurfaceFormatCore::readBINARY
         // interprete colour as a region
         const label stlRegion = stlTri.region();
 
-        Map<label>::const_iterator fnd = regionToPatch.find(stlRegion);
-        label regionI;
-        if (fnd != regionToPatch.end())
+        Map<label>::const_iterator fnd = lookup.find(stlRegion);
+        if (fnd != lookup.end())
         {
+            if (regionI != fnd())
+            {
+                // group appeared out of order
+                sorted_ = false;
+            }
             regionI = fnd();
         }
         else
         {
-            regionI = dynNames.size();
-            dynNames.append(word("patch") + ::Foam::name(regionI));
-            regionToPatch.insert(stlRegion, regionI);
+            regionI = dynSizes.size();
+            lookup.insert(stlRegion, regionI);
+            dynSizes.append(0);
         }
 
         regions_[faceI] = regionI;
+        dynSizes[regionI]++;
 
 #ifdef DEBUG_STLBINARY
         if (prevRegion != regionI)
@@ -198,7 +204,8 @@ bool Foam::fileFormats::STLsurfaceFormatCore::readBINARY
 #endif
     }
 
-    names_.transfer(dynNames);
+    names_.clear();
+    sizes_.transfer(dynSizes);
 
     return true;
 }
@@ -211,10 +218,11 @@ Foam::fileFormats::STLsurfaceFormatCore::STLsurfaceFormatCore
     const fileName& fName
 )
 :
-    binary_(false),
+    sorted_(true),
     points_(0),
     regions_(0),
-    names_(0)
+    names_(0),
+    sizes_(0)
 {
     off_t fileSize = Foam::size(fName);
 
diff --git a/src/surfMesh/surfaceFormats/stl/STLsurfaceFormatCore.H b/src/surfMesh/surfaceFormats/stl/STLsurfaceFormatCore.H
index 399aa0ecb7..0bcb2f1eee 100644
--- a/src/surfMesh/surfaceFormats/stl/STLsurfaceFormatCore.H
+++ b/src/surfMesh/surfaceFormats/stl/STLsurfaceFormatCore.H
@@ -59,7 +59,7 @@ class STLsurfaceFormatCore
 {
     // Private Data
 
-        bool binary_;
+        bool sorted_;
 
         //- The points supporting the facets
         pointField points_;
@@ -70,6 +70,9 @@ class STLsurfaceFormatCore
         //- The solid names, in the order of their first appearance
         List<word> names_;
 
+        //- The solid count, in the order of their first appearance
+        List<label> sizes_;
+
     // Private Member Functions
 
         //- Disallow default bitwise copy construct
@@ -81,10 +84,10 @@ class STLsurfaceFormatCore
         //- Determine the file type
         static int detectBINARY(const fileName&);
 
-        //- Read ASCII, set groupToPatch
+        //- Read ASCII
         bool readASCII(IFstream&, const off_t);
 
-        //- Read BINARY, set maxRegionId
+        //- Read BINARY
         bool readBINARY(IFstream&, const off_t);
 
 public:
@@ -110,27 +113,23 @@ public:
 
     // Member Functions
 
-        //- File was detected to be STL binary
-        bool binary() const
+        //- File read was already sorted
+        bool sorted() const
         {
-            return binary_;
-        }
-
-        //- The number of facets is the number of regions
-        label size() const
-        {
-            return regions_.size();
+            return sorted_;
         }
 
         //- Flush all values
         void clear()
         {
+            sorted_ = true;
             points_.clear();
             regions_.clear();
             names_.clear();
+            sizes_.clear();
         }
 
-        //- Return full access to the faces
+        //- Return full access to the points
         pointField& points()
         {
             return points_;
@@ -148,6 +147,12 @@ public:
             return names_;
         }
 
+        //- The list of solid sizes in the order of their first appearance
+        List<label>& sizes()
+        {
+            return sizes_;
+        }
+
 };
 
 
diff --git a/src/surfMesh/surfaceFormats/tri/TRIsurfaceFormat.C b/src/surfMesh/surfaceFormats/tri/TRIsurfaceFormat.C
index 7c552a81c8..7339786f63 100644
--- a/src/surfMesh/surfaceFormats/tri/TRIsurfaceFormat.C
+++ b/src/surfMesh/surfaceFormats/tri/TRIsurfaceFormat.C
@@ -25,9 +25,7 @@ License
 \*---------------------------------------------------------------------------*/
 
 #include "TRIsurfaceFormat.H"
-#include "IFstream.H"
-#include "IOmanip.H"
-#include "IStringStream.H"
+#include "ListOps.H"
 
 // * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
 
@@ -83,121 +81,76 @@ bool Foam::fileFormats::TRIsurfaceFormat<Face>::read
 {
     this->clear();
 
-    IFstream is(fName);
-    if (!is.good())
+    // read in the values
+    TRIsurfaceFormatCore reader(fName);
+
+    // transfer points
+    this->storedPoints().transfer(reader.points());
+
+    // retrieve the original region information
+    List<label> sizes(xferMove(reader.sizes()));
+    List<label> regions(xferMove(reader.regions()));
+
+    // generate the (sorted) faces
+    List<Face> faceLst(regions.size());
+
+    if (reader.sorted())
     {
-        FatalErrorIn
-        (
-            "fileFormats::TRIsurfaceFormat::read(const fileName&)"
-        )
-            << "Cannot read file " << fName
-            << exit(FatalError);
-    }
-
-    // uses similar structure as STL, just some points
-    DynamicList<point> pointLst;
-    DynamicList<label> regionLst;
-    HashTable<label>   groupToPatch;
-
-    // leave faces that didn't have a group in 0
-    label nUngrouped = 0;
-    label groupID = 0;
-    label maxGroupID = -1;
-
-    while (is.good())
-    {
-        string line = this->getLineNoComment(is);
-
-        // handle continuations ?
-        //          if (line[line.size()-1] == '\\')
-        //          {
-        //              line.substr(0, line.size()-1);
-        //              line += this->getLineNoComment(is);
-        //          }
-
-        IStringStream lineStream(line);
-
-        point p
-        (
-            readScalar(lineStream),
-            readScalar(lineStream),
-            readScalar(lineStream)
-        );
-
-        if (!lineStream) break;
-
-        pointLst.append(p);
-        pointLst.append
-        (
-            point
-            (
-                readScalar(lineStream),
-                readScalar(lineStream),
-                readScalar(lineStream)
-            )
-        );
-        pointLst.append
-        (
-            point
-            (
-                readScalar(lineStream),
-                readScalar(lineStream),
-                readScalar(lineStream)
-            )
-        );
-
-        // Region/colour in .tri file starts with 0x. Skip.
-        // ie, instead of having 0xFF, skip 0 and leave xFF to
-        // get read as a word and name it "patchFF"
-
-        char zero;
-        lineStream >> zero;
-
-        word rawName(lineStream);
-        word groupName("patch" + rawName(1, rawName.size()-1));
-
-        HashTable<label>::const_iterator fnd = groupToPatch.find(groupName);
-
-        if (fnd != groupToPatch.end())
+        // already sorted - generate directly
+        forAll(faceLst, faceI)
         {
-            groupID = fnd();
+            const label startPt = 3*faceI;
+            faceLst[faceI] = triFace(startPt, startPt+1, startPt+2);
         }
-        else
-        {
-            // special treatment if any initial faces were not in a group
-            if (maxGroupID == -1 && regionLst.size())
-            {
-                groupToPatch.insert("patch0", 0);
-                nUngrouped = regionLst.size();
-                maxGroupID = 0;
-            }
-            groupID = ++maxGroupID;
-            groupToPatch.insert(groupName, groupID);
-        }
-
-        regionLst.append(groupID);
     }
-
-    // make our triangles directly
-    List<Face>& faceLst = this->storedFaces();
-    faceLst.setSize(regionLst.size());
-
-    // transfer to normal list
-    this->storedPoints().transfer(pointLst);
-    this->storedRegions().transfer(regionLst);
-
-    forAll(faceLst, faceI)
+    else
     {
-        const label startPt = 3 * faceI;
-        faceLst[faceI] = triFace(startPt, startPt+1, startPt+2);
-    }
+        // unsorted - determine the sorted order:
+        // avoid SortableList since we discard the main list anyhow
+        List<label> faceMap;
+        sortedOrder(regions, faceMap);
 
-    this->setPatches(groupToPatch);
+        // generate sorted faces
+        forAll(faceMap, faceI)
+        {
+            const label startPt = 3*faceMap[faceI];
+            faceLst[faceI] = triFace(startPt, startPt+1, startPt+2);
+        }
+    }
+    regions.clear();
+
+    // transfer:
+    this->storedFaces().transfer(faceLst);
+
+    this->addPatches(sizes);
     this->stitchFaces(SMALL);
     return true;
 }
 
 
+template<class Face>
+void Foam::fileFormats::TRIsurfaceFormat<Face>::write
+(
+    Ostream& os,
+    const MeshedSurface<Face>& surf
+)
+{
+    const pointField& pointLst = surf.points();
+    const List<Face>& faceLst  = surf.faces();
+    const List<surfGroup>& patchLst = surf.patches();
+
+    label faceIndex = 0;
+    forAll(patchLst, patchI)
+    {
+        forAll(patchLst[patchI], patchFaceI)
+        {
+            const Face& f = faceLst[faceIndex++];
+            writeShell(os, pointLst, f, patchI);
+        }
+    }
+}
+
+
 template<class Face>
 void Foam::fileFormats::TRIsurfaceFormat<Face>::write
 (
@@ -241,27 +194,4 @@ void Foam::fileFormats::TRIsurfaceFormat<Face>::write
     }
 }
 
-
-template<class Face>
-void Foam::fileFormats::TRIsurfaceFormat<Face>::write
-(
-    Ostream& os,
-    const MeshedSurface<Face>& surf
-)
-{
-    const pointField& pointLst = surf.points();
-    const List<Face>& faceLst  = surf.faces();
-    const List<surfGroup>& patchLst = surf.patches();
-
-    label faceIndex = 0;
-    forAll(patchLst, patchI)
-    {
-        forAll(patchLst[patchI], patchFaceI)
-        {
-            const Face& f = faceLst[faceIndex++];
-            writeShell(os, pointLst, f, patchI);
-        }
-    }
-}
-
 // ************************************************************************* //
diff --git a/src/surfMesh/surfaceFormats/tri/TRIsurfaceFormat.H b/src/surfMesh/surfaceFormats/tri/TRIsurfaceFormat.H
index ac5e473bf3..3f6f04d5e6 100644
--- a/src/surfMesh/surfaceFormats/tri/TRIsurfaceFormat.H
+++ b/src/surfMesh/surfaceFormats/tri/TRIsurfaceFormat.H
@@ -28,6 +28,10 @@ Class
 Description
     Provide a means of reading/writing .tri format.
 
+Note
+    For efficiency, the regions are sorted before creating the faces.
+    The class is thus derived from MeshedSurface.
+
 SourceFiles
     TRIsurfaceFormat.C
 
@@ -36,6 +40,7 @@ SourceFiles
 #ifndef TRIsurfaceFormat_H
 #define TRIsurfaceFormat_H
 
+#include "TRIsurfaceFormatCore.H"
 #include "Ostream.H"
 #include "OFstream.H"
 #include "MeshedSurface.H"
@@ -49,13 +54,13 @@ namespace fileFormats
 {
 
 /*---------------------------------------------------------------------------*\
-                       Class TRIsurfaceFormat Declaration
+                     Class TRIsurfaceFormat Declaration
 \*---------------------------------------------------------------------------*/
 
 template<class Face>
 class TRIsurfaceFormat
 :
-    public UnsortedMeshedSurface<Face>
+    public MeshedSurface<Face>
 {
     // Private Member Functions
 
@@ -83,12 +88,12 @@ public:
     // Selectors
 
         //- Read file and return surface
-        static autoPtr<UnsortedMeshedSurface<Face> > New
+        static autoPtr<MeshedSurface<Face> > New
         (
             const fileName& fName
         )
         {
-            return autoPtr<UnsortedMeshedSurface<Face> >
+            return autoPtr<MeshedSurface<Face> >
             (
                 new TRIsurfaceFormat<Face>(fName)
             );
@@ -140,7 +145,6 @@ public:
         }
 
         //- Write object
-        //  By default, the output is not sorted by regions
         virtual void write(Ostream& os) const
         {
             write(os, *this);
diff --git a/src/surfMesh/surfaceFormats/tri/TRIsurfaceFormatCore.C b/src/surfMesh/surfaceFormats/tri/TRIsurfaceFormatCore.C
new file mode 100644
index 0000000000..99e07d7924
--- /dev/null
+++ b/src/surfMesh/surfaceFormats/tri/TRIsurfaceFormatCore.C
@@ -0,0 +1,182 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | Copyright (C) 1991-2008 OpenCFD Ltd.
+     \\/     M anipulation  |
+-------------------------------------------------------------------------------
+License
+    This file is part of OpenFOAM.
+
+    OpenFOAM is free software; you can redistribute it and/or modify it
+    under the terms of the GNU General Public License as published by the
+    Free Software Foundation; either version 2 of the License, or (at your
+    option) any later version.
+
+    OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
+    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+    for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with OpenFOAM; if not, write to the Free Software Foundation,
+    Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+
+\*---------------------------------------------------------------------------*/
+
+#include "TRIsurfaceFormat.H"
+#include "IFstream.H"
+#include "IOmanip.H"
+#include "IStringStream.H"
+#include "Map.H"
+
+// * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
+
+// * * * * * * * * * * * * * Private Member Functions  * * * * * * * * * * * //
+
+// * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
+
+Foam::fileFormats::TRIsurfaceFormatCore::TRIsurfaceFormatCore
+(
+    const fileName& fName
+)
+:
+    sorted_(true),
+    points_(0),
+    regions_(0),
+    sizes_(0)
+{
+    read(fName);
+}
+
+// * * * * * * * * * * * * * * * * Destructors * * * * * * * * * * * * * * * //
+
+Foam::fileFormats::TRIsurfaceFormatCore::~TRIsurfaceFormatCore()
+{}
+
+
+// * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
+
+bool Foam::fileFormats::TRIsurfaceFormatCore::read
+(
+    const fileName& fName
+)
+{
+    this->clear();
+    sorted_ = true;
+
+    IFstream is(fName);
+    if (!is.good())
+    {
+        FatalErrorIn
+        (
+            "fileFormats::TRIsurfaceFormatCore::read(const fileName&)"
+        )
+            << "Cannot read file " << fName
+            << exit(FatalError);
+    }
+
+    // uses similar structure as STL, just some points
+    // the rest of the reader resembles the STL binary reader
+    DynamicList<point> dynPoints;
+    DynamicList<label> dynRegions;
+    DynamicList<label> dynSizes;
+    HashTable<label>   lookup;
+
+    // place faces without a group in patch0
+    label regionI = 0;
+    dynSizes.append(regionI);
+    lookup.insert("patch0", regionI);
+
+    while (is.good())
+    {
+        string line = this->getLineNoComment(is);
+
+        // handle continuations ?
+        //          if (line[line.size()-1] == '\\')
+        //          {
+        //              line.substr(0, line.size()-1);
+        //              line += this->getLineNoComment(is);
+        //          }
+
+        IStringStream lineStream(line);
+
+        point p
+        (
+            readScalar(lineStream),
+            readScalar(lineStream),
+            readScalar(lineStream)
+        );
+
+        if (!lineStream) break;
+
+        dynPoints.append(p);
+        dynPoints.append
+        (
+            point
+            (
+                readScalar(lineStream),
+                readScalar(lineStream),
+                readScalar(lineStream)
+            )
+        );
+        dynPoints.append
+        (
+            point
+            (
+                readScalar(lineStream),
+                readScalar(lineStream),
+                readScalar(lineStream)
+            )
+        );
+
+        // Region/colour in .tri file starts with 0x. Skip.
+        // ie, instead of having 0xFF, skip 0 and leave xFF to
+        // get read as a word and name it "patchFF"
+
+        char zero;
+        lineStream >> zero;
+
+        word rawName(lineStream);
+        word name("patch" + rawName(1, rawName.size()-1));
+
+        HashTable<label>::const_iterator fnd = lookup.find(name);
+        if (fnd != lookup.end())
+        {
+            if (regionI != fnd())
+            {
+                // group appeared out of order
+                sorted_ = false;
+            }
+            regionI = fnd();
+        }
+        else
+        {
+            regionI = dynSizes.size();
+            lookup.insert(name, regionI);
+            dynSizes.append(0);
+        }
+
+        dynRegions.append(regionI);
+        dynSizes[regionI]++;
+    }
+
+    // transfer to normal lists
+    points_.transfer(dynPoints);
+    regions_.transfer(dynRegions);
+
+    if (dynSizes[0] == 0)
+    {
+        // no ungrouped patches, copy sub-list
+        sizes_ = SubList<label>(dynSizes, dynSizes.size()-1, 1);
+    }
+    else
+    {
+        sizes_.transfer(dynSizes);
+    }
+
+    return true;
+}
+
+
+// ************************************************************************* //
diff --git a/src/surfMesh/surfaceFormats/tri/TRIsurfaceFormatCore.H b/src/surfMesh/surfaceFormats/tri/TRIsurfaceFormatCore.H
new file mode 100644
index 0000000000..3b9b1d907a
--- /dev/null
+++ b/src/surfMesh/surfaceFormats/tri/TRIsurfaceFormatCore.H
@@ -0,0 +1,143 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | Copyright (C) 1991-2008 OpenCFD Ltd.
+     \\/     M anipulation  |
+-------------------------------------------------------------------------------
+License
+    This file is part of OpenFOAM.
+
+    OpenFOAM is free software; you can redistribute it and/or modify it
+    under the terms of the GNU General Public License as published by the
+    Free Software Foundation; either version 2 of the License, or (at your
+    option) any later version.
+
+    OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
+    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+    for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with OpenFOAM; if not, write to the Free Software Foundation,
+    Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+
+Class
+    Foam::fileFormats::TRIsurfaceFormatCore
+
+Description
+    Internal class used by the TRIsurfaceFormat
+
+SourceFiles
+    TRIsurfaceFormatCore.C
+
+\*---------------------------------------------------------------------------*/
+
+#ifndef TRIsurfaceFormatCore_H
+#define TRIsurfaceFormatCore_H
+
+#include "surfaceFormatsCore.H"
+#include "triFace.H"
+#include "IFstream.H"
+#include "Ostream.H"
+#include "OFstream.H"
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+namespace Foam
+{
+namespace fileFormats
+{
+
+/*---------------------------------------------------------------------------*\
+                   Class TRIsurfaceFormatCore Declaration
+\*---------------------------------------------------------------------------*/
+
+class TRIsurfaceFormatCore
+:
+    public surfaceFormatsCore
+{
+    // Private Data
+
+        bool sorted_;
+
+        //- The points supporting the facets
+        pointField points_;
+
+        //- The regions associated with the faces
+        List<label> regions_;
+
+        //- The solid count, in the order of their first appearance
+        List<label> sizes_;
+
+    // Private Member Functions
+
+        //- Disallow default bitwise copy construct
+        TRIsurfaceFormatCore(const TRIsurfaceFormatCore&);
+
+        //- Disallow default bitwise assignment
+        void operator=(const TRIsurfaceFormatCore&);
+
+        bool read(const fileName&);
+
+public:
+
+    // Constructors
+
+        //- Read from file, filling in the information
+        TRIsurfaceFormatCore(const fileName&);
+
+    // Destructor
+
+        ~TRIsurfaceFormatCore();
+
+    // Member Functions
+
+        //- File read was already sorted
+        bool sorted() const
+        {
+            return sorted_;
+        }
+
+        //- Flush all values
+        void clear()
+        {
+            sorted_ = true;
+            points_.clear();
+            regions_.clear();
+            sizes_.clear();
+        }
+
+        //- Return full access to the points
+        pointField& points()
+        {
+            return points_;
+        }
+
+        //- Return full access to the regions
+        List<label>& regions()
+        {
+            return regions_;
+        }
+
+        //- The list of region sizes in the order of their first appearance
+        List<label>& sizes()
+        {
+            return sizes_;
+        }
+
+};
+
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+} // End namespace fileFormats
+} // End namespace Foam
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+#endif
+
+// ************************************************************************* //
diff --git a/src/surfMesh/surfaceFormats/tri/TRIsurfaceFormatRunTime.C b/src/surfMesh/surfaceFormats/tri/TRIsurfaceFormatRunTime.C
index 43e0cdf492..488a3efb24 100644
--- a/src/surfMesh/surfaceFormats/tri/TRIsurfaceFormatRunTime.C
+++ b/src/surfMesh/surfaceFormats/tri/TRIsurfaceFormatRunTime.C
@@ -38,7 +38,7 @@ namespace fileFormats
 
 addNamedTemplatedToRunTimeSelectionTable
 (
-    UnsortedMeshedSurface,
+    MeshedSurface,
     TRIsurfaceFormat,
     face,
     fileExtension,
@@ -46,7 +46,7 @@ addNamedTemplatedToRunTimeSelectionTable
 );
 addNamedTemplatedToRunTimeSelectionTable
 (
-    UnsortedMeshedSurface,
+    MeshedSurface,
     TRIsurfaceFormat,
     triFace,
     fileExtension,