diff --git a/extern/recastnavigation/BlenderNavMesh/NavMeshConversion.cpp b/extern/recastnavigation/BlenderNavMesh/NavMeshConversion.cpp
index ed02a27cc43..ca11ed68c54 100644
--- a/extern/recastnavigation/BlenderNavMesh/NavMeshConversion.cpp
+++ b/extern/recastnavigation/BlenderNavMesh/NavMeshConversion.cpp
@@ -310,11 +310,18 @@ bool buildNavMeshData(const int nverts, const float* verts,
 	{
 		memcpy(dtris+3*2*i, tris+3*dtrisToTrisMap[i], sizeof(unsigned short)*3);
 	}
-	//create new recast data corresponded to dtris
+	//create new recast data corresponded to dtris and renumber for continious indices
+	int prevPolyIdx=-1, curPolyIdx, newPolyIdx=0;
 	dtrisToPolysMap = new int[ndtris];
 	for (int i=0; i<ndtris; i++)
 	{
-		dtrisToPolysMap[i] = recastData[trisToFacesMap[dtrisToTrisMap[i]]];
+		curPolyIdx = recastData[trisToFacesMap[dtrisToTrisMap[i]]];
+		if (curPolyIdx!=prevPolyIdx)
+		{
+			newPolyIdx++;
+			prevPolyIdx=curPolyIdx;
+		}
+		dtrisToPolysMap[i] = newPolyIdx;
 	}
 
 
diff --git a/source/blender/editors/object/object_navmesh.cpp b/source/blender/editors/object/object_navmesh.cpp
index f7527e2d5d5..b8728e35a54 100644
--- a/source/blender/editors/object/object_navmesh.cpp
+++ b/source/blender/editors/object/object_navmesh.cpp
@@ -43,6 +43,8 @@ extern "C"
 #include "BKE_depsgraph.h"
 #include "BKE_context.h"
 #include "BKE_mesh.h"
+#include "BKE_modifier.h"
+#include "BKE_scene.h"
 #include "BKE_DerivedMesh.h"
 #include "BKE_cdderivedmesh.h"
 #include "BLI_editVert.h"
@@ -57,6 +59,9 @@ extern "C"
 /*mesh/mesh_intern.h */
 extern struct EditVert *addvertlist(EditMesh *em, float *vec, struct EditVert *example);
 extern struct EditFace *addfacelist(EditMesh *em, struct EditVert *v1, struct EditVert *v2, struct EditVert *v3, struct EditVert *v4, struct EditFace *example, struct EditFace *exampleEdges);
+extern void free_vertlist(EditMesh *em, ListBase *edve);
+extern void free_edgelist(EditMesh *em, ListBase *lb);
+extern void free_facelist(EditMesh *em, ListBase *lb);
 
 #include "WM_api.h"
 #include "WM_types.h"
@@ -301,23 +306,43 @@ static bool buildNavMesh(const RecastData& recastParams, int nverts, float* vert
 	return true;
 }
 
-static Object* createRepresentation(bContext *C, rcPolyMesh*& pmesh, rcPolyMeshDetail*& dmesh)
+static Object* createRepresentation(bContext *C, rcPolyMesh*& pmesh, rcPolyMeshDetail*& dmesh, Base* base)
 {
-	Object *obedit;
 	float co[3], rot[3];
 	EditMesh *em;
 	int i,j, k, polyverts;
 	unsigned short* v;
 	int face[3];
 	Scene *scene= CTX_data_scene(C);
-
+	Object* obedit;
+	int createob = base==NULL;
 	zero_v3(co);
 	zero_v3(rot);
-	obedit = ED_object_add_type(C, OB_MESH, co, rot, FALSE, 1);
-	ED_object_enter_editmode(C, EM_DO_UNDO|EM_IGNORE_LAYER);
+	if (createob)
+	{
+		//create new object
+		obedit = ED_object_add_type(C, OB_MESH, co, rot, FALSE, 1);
+	}
+	else
+	{
+		obedit = base->object;
+		scene_select_base(scene, base);
+		copy_v3_v3(obedit->loc, co);
+		copy_v3_v3(obedit->rot, rot);
+	}
 
+	ED_object_enter_editmode(C, EM_DO_UNDO|EM_IGNORE_LAYER);
 	em = BKE_mesh_get_editmesh(((Mesh *)obedit->data));
 
+	if (!createob)
+	{
+		//clear
+		if(em->verts.first) free_vertlist(em, &em->verts);
+		if(em->edges.first) free_edgelist(em, &em->edges);
+		if(em->faces.first) free_facelist(em, &em->faces);
+		if(em->selected.first) BLI_freelistN(&(em->selected));
+	}
+
 	//create verts for polygon mesh
 	for(i = 0; i < pmesh->nverts; i++) {
 		v = &pmesh->verts[3*i];
@@ -392,13 +417,20 @@ static Object* createRepresentation(bContext *C, rcPolyMesh*& pmesh, rcPolyMeshD
 	ED_object_exit_editmode(C, EM_FREEDATA); 
 	WM_event_add_notifier(C, NC_OBJECT|ND_DRAW, obedit);
 
-	obedit->gameflag &= ~OB_COLLISION;
-	obedit->gameflag |= OB_NAVMESH;
-	obedit->body_type = OB_BODY_TYPE_NAVMESH;
-	rename_id((ID *)obedit, "Navmesh");
+	if (createob)
+	{
+		obedit->gameflag &= ~OB_COLLISION;
+		obedit->gameflag |= OB_NAVMESH;
+		obedit->body_type = OB_BODY_TYPE_NAVMESH;
+		rename_id((ID *)obedit, "Navmesh");
+	}
+	
+	ModifierData *md= modifiers_findByType(obedit, eModifierType_NavMesh);
+	if (!md)
+	{
+		ED_object_modifier_add(NULL, scene, obedit, NULL, eModifierType_NavMesh);
+	}
 
-	ED_object_modifier_add(NULL, scene, obedit, NULL, eModifierType_NavMesh);
-	//ModifierData *md= modifiers_findByType(ob, eModifierType_NavMesh);
 	return obedit;
 }
 
@@ -411,15 +443,22 @@ static int create_navmesh_exec(bContext *C, wmOperator *op)
 	rcPolyMesh* pmesh;
 	rcPolyMeshDetail* dmesh;
 	LinkNode* obs = NULL;
+	Base* navmeshBase = NULL;
 	CTX_DATA_BEGIN(C, Base*, base, selected_editable_bases)
 	{
-		BLI_linklist_append(&obs, (void*)base->object);
+		if (base->object->body_type==OB_BODY_TYPE_NAVMESH)
+		{
+			if (!navmeshBase || base==CTX_data_active_base(C))
+				navmeshBase = base;
+		}
+		else
+			BLI_linklist_append(&obs, (void*)base->object);
 	}		
 	CTX_DATA_END;
 	createVertsTrisData(C, obs, nverts, verts, ntris, tris);
 	BLI_linklist_free(obs, NULL);
 	buildNavMesh(scene->gm.recastData, nverts, verts, ntris, tris, pmesh, dmesh);
-	createRepresentation(C, pmesh, dmesh);
+	createRepresentation(C, pmesh, dmesh, navmeshBase);
 
 	return OPERATOR_FINISHED;
 }
@@ -520,7 +559,6 @@ static int findFreeNavPolyIndex(EditMesh* em)
 	qsort(indices, numfaces, sizeof(int), compare);
 	//search first free index
 	int freeIdx = 1;
-	int maxIdx = indices[numfaces-1];
 	for (int i=0; i<numfaces; i++)
 	{
 		if (indices[i]==freeIdx)
diff --git a/source/blender/makesrna/intern/rna_modifier.c b/source/blender/makesrna/intern/rna_modifier.c
index 83252e404e0..5c5f854f05b 100644
--- a/source/blender/makesrna/intern/rna_modifier.c
+++ b/source/blender/makesrna/intern/rna_modifier.c
@@ -61,7 +61,6 @@ EnumPropertyItem modifier_type_items[] ={
 	{eModifierType_Solidify, "SOLIDIFY", ICON_MOD_SOLIDIFY, "Solidify", ""},
 	{eModifierType_Subsurf, "SUBSURF", ICON_MOD_SUBSURF, "Subdivision Surface", ""},
 	{eModifierType_UVProject, "UV_PROJECT", ICON_MOD_UVPROJECT, "UV Project", ""},
-	{eModifierType_NavMesh, "NAVMESH", ICON_MOD_DECIM, "Navigation mesh", ""},
 	{0, "", 0, "Deform", ""},
 	{eModifierType_Armature, "ARMATURE", ICON_MOD_ARMATURE, "Armature", ""},
 	{eModifierType_Cast, "CAST", ICON_MOD_CAST, "Cast", ""},
@@ -84,6 +83,7 @@ EnumPropertyItem modifier_type_items[] ={
 	{eModifierType_Smoke, "SMOKE", ICON_MOD_SMOKE, "Smoke", ""},
 	{eModifierType_Softbody, "SOFT_BODY", ICON_MOD_SOFT, "Soft Body", ""},
 	{eModifierType_Surface, "SURFACE", ICON_MOD_PHYSICS, "Surface", ""},
+	{eModifierType_NavMesh, "NAVMESH", ICON_MOD_PHYSICS, "Navigation mesh", ""},
 	{0, NULL, 0, NULL, NULL}};
 
 #ifdef RNA_RUNTIME
diff --git a/source/blender/modifiers/intern/MOD_navmesh.cpp b/source/blender/modifiers/intern/MOD_navmesh.cpp
index 8f914245888..851615769ab 100644
--- a/source/blender/modifiers/intern/MOD_navmesh.cpp
+++ b/source/blender/modifiers/intern/MOD_navmesh.cpp
@@ -30,7 +30,7 @@
 #include "NavMeshConversion.h"
 
 extern "C"{
-
+#include "DNA_mesh_types.h"
 #include "DNA_meshdata_types.h"
 #include "BLI_math.h"
 #include "BKE_cdderivedmesh.h"
@@ -125,9 +125,6 @@ static void navDM_drawFacesSolid(DerivedMesh *dm,
 static DerivedMesh *createNavMeshForVisualization(NavMeshModifierData *mmd,DerivedMesh *dm)
 {
 	DerivedMesh *result;
-	int numVerts, numEdges, numFaces;
-	int maxVerts = dm->getNumVerts(dm);
-	int maxEdges = dm->getNumEdges(dm);
 	int maxFaces = dm->getNumFaces(dm);
 
 	result = CDDM_copy(dm);
@@ -209,9 +206,39 @@ static DerivedMesh *applyModifier(ModifierData *md, Object *ob, DerivedMesh *der
 {
 	DerivedMesh *result = NULL;
 	NavMeshModifierData *nmmd = (NavMeshModifierData*) md;
+	bool hasRecastData = CustomData_has_layer(&derivedData->faceData, CD_PROP_INT)>0;
+	if (ob->body_type!=OB_BODY_TYPE_NAVMESH || !hasRecastData )
+	{
+		//convert to nav mesh object:
+		//1)set physics type
+		ob->gameflag &= ~OB_COLLISION;
+		ob->gameflag |= OB_NAVMESH;
+		ob->body_type = OB_BODY_TYPE_NAVMESH;
+		//2)add and init recast data layer
+		if (!hasRecastData)
+		{
+			int numFaces = derivedData->getNumFaces(derivedData);
+			CustomData_add_layer_named(&derivedData->faceData, CD_PROP_INT, CD_CALLOC, NULL, numFaces, "recastData");
+			int* recastData = (int*)CustomData_get_layer(&derivedData->faceData, CD_PROP_INT);
+			for (int i=0; i<numFaces; i++)
+			{
+				recastData[i] = i+1;
+			}
 
-	if (ob->body_type==OB_BODY_TYPE_NAVMESH)
-		result = createNavMeshForVisualization(nmmd, derivedData);
+			Mesh* obmesh = (Mesh *)ob->data;
+			if (obmesh)
+			{
+				CustomData_add_layer_named(&obmesh->fdata, CD_PROP_INT, CD_CALLOC, NULL, numFaces, "recastData");
+				int* recastData = (int*)CustomData_get_layer(&obmesh->fdata, CD_PROP_INT);
+				for (int i=0; i<numFaces; i++)
+				{
+					recastData[i] = i+1;
+				}
+			}
+		}
+	}
+
+	result = createNavMeshForVisualization(nmmd, derivedData);
 	
 	return result;
 }
@@ -223,7 +250,7 @@ ModifierTypeInfo modifierType_NavMesh = {
 	/* structSize */        sizeof(NavMeshModifierData),
 	/* type */              eModifierTypeType_Constructive,
 	/* flags */             (ModifierTypeFlag) (eModifierTypeFlag_AcceptsMesh
-							| eModifierTypeFlag_NoUserAdd),
+							| eModifierTypeFlag_Single),
 	/* copyData */          copyData,
 	/* deformVerts */       0,
 	/* deformVertsEM */     0,
diff --git a/source/gameengine/Ketsji/KX_SteeringActuator.cpp b/source/gameengine/Ketsji/KX_SteeringActuator.cpp
index 78b6247b775..f70826d16f9 100644
--- a/source/gameengine/Ketsji/KX_SteeringActuator.cpp
+++ b/source/gameengine/Ketsji/KX_SteeringActuator.cpp
@@ -173,13 +173,15 @@ bool KX_SteeringActuator::Update(double curtime, bool frame)
 		const MT_Point3& mypos = obj->NodeGetWorldPosition();
 		const MT_Point3& targpos = m_target->NodeGetWorldPosition();
 		MT_Vector3 vectotarg = targpos - mypos;
+		MT_Vector3 vectotarg2d = vectotarg;
+		vectotarg2d.z() = 0;
 		MT_Vector3 steervec = MT_Vector3(0, 0, 0);
 		bool apply_steerforce = false;
 		bool terminate = true;
 
 		switch (m_mode) {
 			case KX_STEERING_SEEK:
-				if (vectotarg.length2()>m_distance*m_distance)
+				if (vectotarg2d.length2()>m_distance*m_distance)
 				{
 					terminate = false;
 					steervec = vectotarg;
@@ -188,7 +190,7 @@ bool KX_SteeringActuator::Update(double curtime, bool frame)
 				}
 				break;
 			case KX_STEERING_FLEE:
-				if (vectotarg.length2()<m_distance*m_distance)
+				if (vectotarg2d.length2()<m_distance*m_distance)
 				{
 					terminate = false;
 					steervec = -vectotarg;