===Python API===

New keyword parameters for Mesh.faces.extend() method:
  * ignoreDups: turns off checks for duplicate faces in the input list and
    existing mesh faces.  Intended for constructing new meshes where the
    faces are known to be unique.
  * indexList: makes the method return a list of new faces indices, which
    can be used to index new faces to add other attributes like color.  If
    duplicate faces are removed, None is placed in their list slot.

source/blender/python/api2_2x/Mesh.c

@@ -4594,7 +4594,8 @@ static PyObject *MFaceSeq_nextIter( BPy_MFaceSeq * self )
  *
  ************************************************************************/
 
-static PyObject *MFaceSeq_extend( BPy_MEdgeSeq * self, PyObject *args )
+static PyObject *MFaceSeq_extend( BPy_MEdgeSeq * self, PyObject *args,
+	  PyObject *keywds )
 {
 	/*
 	 * (a) check input for valid edge objects, faces which consist of
@@ -4615,15 +4616,27 @@ static PyObject *MFaceSeq_extend( BPy_MEdgeSeq * self, PyObject *args )
 	PyObject *tmp;
 	MFace *tmpface;
 	Mesh *mesh = self->mesh;
+	int ignore_dups = 0;
+	PyObject *return_list = NULL;
 
 	/* before we try to add faces, add edges; if it fails; exit */
 
 	tmp = MEdgeSeq_extend( self, args );
 	if( !tmp )
 		return NULL;
-
 	Py_DECREF( tmp );
 
+	/* process any keyword arguments */
+	if( keywds ) {
+		PyObject *res = PyDict_GetItemString( keywds, "ignoreDups" );
+		if( res )
+			ignore_dups = PyObject_IsTrue( res );
+
+		res = PyDict_GetItemString( keywds, "indexList" );
+		if( res && PyObject_IsTrue( res ) )
+			return_list = PyList_New( 0 );
+	}
+
 	/* make sure we get a tuple of sequences of something */
 
 	switch( PySequence_Size( args ) ) {
@@ -4775,9 +4788,6 @@ static PyObject *MFaceSeq_extend( BPy_MEdgeSeq * self, PyObject *args )
 		++tmppair;
 	}
 
-	/* sort the new face pairs */
-	qsort( newpair, new_face_count, sizeof(SrchFaces), mface_comp );
-
 	/*
 	 * find duplicates in the new list and mark.  if it's a duplicate,
 	 * then mark by setting second vert index to 0 (a real edge won't have
@@ -4788,6 +4798,11 @@ static PyObject *MFaceSeq_extend( BPy_MEdgeSeq * self, PyObject *args )
 
 	tmppair = newpair;	/* "last good edge" */
 	tmppair2 = &tmppair[1];	/* "current candidate edge" */
+	if( !ignore_dups ) {
+
+	/* sort the new face pairs */
+		qsort( newpair, new_face_count, sizeof(SrchFaces), mface_comp );
+
 		for( i = 0; i < new_face_count; ++i ) {
 			if( mface_comp( tmppair, tmppair2 ) )
 				tmppair = tmppair2;	/* last != current, so current == last */
@@ -4797,9 +4812,10 @@ static PyObject *MFaceSeq_extend( BPy_MEdgeSeq * self, PyObject *args )
 			}
 			tmppair2++;
 		}
+	}
 
 	/* if mesh has faces, see if any of the new faces are already in it */
-	if( mesh->totface ) {
+	if( mesh->totface && !ignore_dups ) {
 		oldpair = (SrchFaces *)MEM_callocN( sizeof(SrchFaces)*mesh->totface,
 				"MFacePairs" );
 
@@ -4837,8 +4853,7 @@ static PyObject *MFaceSeq_extend( BPy_MEdgeSeq * self, PyObject *args )
 
 	/* eliminate new faces already in the mesh */
 		tmppair = newpair;
-		i = good_faces;
-		while( i ) {
+		for( i = good_faces; i ; ) {
 			if( tmppair->v[1] ) {
 				if( bsearch( tmppair, oldpair, mesh->totface, 
 						sizeof(SrchFaces), mface_comp ) ) {
@@ -4853,7 +4868,7 @@ static PyObject *MFaceSeq_extend( BPy_MEdgeSeq * self, PyObject *args )
 	}
 
 	/* if any new faces are left, add to list */
-	if( good_faces ) {
+	if( good_faces || return_list ) {
 		int totface = mesh->totface+good_faces;	/* new face count */
 
 	/* if mesh has tfaces, reallocate them first */
@@ -4882,7 +4897,9 @@ static PyObject *MFaceSeq_extend( BPy_MEdgeSeq * self, PyObject *args )
 		}
 
 	/* sort the faces back into their original input list order */
-		qsort( newpair, new_face_count, sizeof(SrchFaces), mface_index_comp );
+		if( !ignore_dups )
+			qsort( newpair, new_face_count, sizeof(SrchFaces),
+					mface_index_comp );
 
 	/* allocate new face list */
 		tmpface = MEM_callocN(totface*sizeof(MFace), "Mesh_addFaces");
@@ -4898,6 +4915,9 @@ static PyObject *MFaceSeq_extend( BPy_MEdgeSeq * self, PyObject *args )
 		tmpface = &mesh->mface[mesh->totface];
 		tmppair = newpair;
 
+		if( return_list )
+			good_faces = new_face_count;	/* assume all faces good to start */
+			
 	/* as we find a good face, add it */
 		while ( good_faces ) {
 			if( tmppair->v[1] ) {
@@ -4918,9 +4938,18 @@ static PyObject *MFaceSeq_extend( BPy_MEdgeSeq * self, PyObject *args )
 				tmpface->v4 = tmppair->v[index[3]];
 
 				tmpface->flag = 0;
+
+				if( return_list )
+					PyList_Append( return_list, 
+							PyInt_FromLong( mesh->totface ) );
+
 				mesh->totface++;
 				++tmpface;
 				--good_faces;
+			} else if( return_list ) {
+				Py_INCREF( Py_None );
+				PyList_Append( return_list, Py_None );
+				--good_faces;
 			}
 			tmppair++;
 		}
@@ -4930,6 +4959,10 @@ static PyObject *MFaceSeq_extend( BPy_MEdgeSeq * self, PyObject *args )
 	mesh_update( mesh );
 	Py_DECREF ( args );
 	MEM_freeN( newpair );
+
+	if( return_list )
+		return return_list;
+	else
 		Py_RETURN_NONE;
 }
 
@@ -5177,7 +5210,7 @@ static PyObject *MFaceSeq_selected( BPy_MFaceSeq * self )
 }
 
 static struct PyMethodDef BPy_MFaceSeq_methods[] = {
-	{"extend", (PyCFunction)MFaceSeq_extend, METH_VARARGS,
+	{"extend", (PyCFunction)MFaceSeq_extend, METH_VARARGS|METH_KEYWORDS,
 		"add faces to mesh"},
 	{"delete", (PyCFunction)MFaceSeq_delete, METH_VARARGS,
 		"delete faces from mesh"},

source/blender/python/api2_2x/doc/Mesh.py

@@ -613,7 +613,7 @@ class MFaceSeq:
     This object provides sequence and iterator access to the mesh's faces.
   """
 
-  def extend(vertseq):
+  def extend(vertseq,ignoreDups=True,indexList=True):
     """
     Add zero or more faces and edges to the mesh.  Faces which already exist
     in the mesh, or faces which contain the same vertex multiple times are
@@ -634,6 +634,16 @@ class MFaceSeq:
     @type vertseq: sequence(s) of MVerts
     @param vertseq: either two to four ints or MVerts, or sequence (list or
     tuple) of sequences each containing two to four ints or MVerts.
+    @type ignoreDups: boolean
+    @param ignoreDups: keyword parameter (default is False).  If supplied and
+    True, do not check the input list or mesh for duplicate faces.  This can
+    speed up scripts but can prossibly produce undesirable effects.  Only
+    use if you know what you're doing.
+    @type indexList: boolean
+    @param indexList: keyword parameter (default is False).  If supplied and
+    True, the method will return a list representing the new index for each
+    face in the input list.  If faces are removed as duplicates, None is
+    inserted in place of the index.
     """
 
   def delete(deledges, faces):