Sculpt: Multires

* Displacement coordinates are now stored differently, as a grid per
  face corner. This means there is duplication of coordinates, especially
  at low subdivision levels, but the simpler implementation justifies it
  I think.
* ToDo: conversion of existing multires files (2.4x or 2.5x), loading them
  may even crash now.
* Editmode preservation/interpolation code also has not been updated yet.

* Multires now works on the CCGDerivedMesh grids instead of CDDerivedMesh,
  which should be more memory efficient.
* There are still bad memory peaks (if you're using 32bit) when subdividing
  or propagating displacements. Though at least there should be no huge
  memory blocks allocated, which windows is now to have trouble with.
* Still found some weird spike artifacts at lower multires levels, some also
  happening before this commit. Perhaps computation of tangents needs to be
  tweaked more.

* Multires modifier now has viewport, sculpt and render levels. Also the
  levels have been made consistent with subsurf, previously the same level
  of subdivision was one less for multires.
* Both multires and subsurf modifier now can have their subdivision level
  set to 0 for no subdivision.

15 files changed, 582 insertions, 1276 deletions

diff --git a/source/blender/blenkernel/BKE_modifier.h b/source/blender/blenkernel/BKE_modifier.h
index 245db7e35ff..3018f89178e 100644
--- a/source/blender/blenkernel/BKE_modifier.h
+++ b/source/blender/blenkernel/BKE_modifier.h
@@ -228,7 +228,7 @@ typedef struct ModifierTypeInfo {
 	 *
 	 * This function is optional (assumes never disabled if not present).
 	 */
-	int (*isDisabled)(struct ModifierData *md);
+	int (*isDisabled)(struct ModifierData *md, int userRenderParams);
 
 	/* Add the appropriate relations to the DEP graph depending on the
 	 * modifier data. 
diff --git a/source/blender/blenkernel/BKE_multires.h b/source/blender/blenkernel/BKE_multires.h
index a331479cad1..53ead3a5eda 100644
--- a/source/blender/blenkernel/BKE_multires.h
+++ b/source/blender/blenkernel/BKE_multires.h
@@ -39,23 +39,6 @@ typedef struct MultiresSubsurf {
 	int local_mmd;
 } MultiresSubsurf;
 
-/* MultiresDM */
-struct Object *MultiresDM_get_object(struct DerivedMesh *dm);
-struct Mesh *MultiresDM_get_mesh(struct DerivedMesh *dm);
-struct DerivedMesh *MultiresDM_new(struct MultiresSubsurf *, struct DerivedMesh*, int, int, int);
-void *MultiresDM_get_vertnorm(struct DerivedMesh *);
-void *MultiresDM_get_orco(struct DerivedMesh *);
-struct MVert *MultiresDM_get_subco(struct DerivedMesh *);
-struct ListBase *MultiresDM_get_vert_face_map(struct DerivedMesh *);
-struct ListBase *MultiresDM_get_vert_edge_map(struct DerivedMesh *);
-int *MultiresDM_get_face_offsets(struct DerivedMesh *);
-int MultiresDM_get_totlvl(struct DerivedMesh *);
-int MultiresDM_get_lvl(struct DerivedMesh *);
-void MultiresDM_set_update(struct DerivedMesh *, void (*)(struct DerivedMesh*));
-
-/* The displacements will only be updated when
-   the MultiresDM has been marked as modified */
-void MultiresDM_mark_as_modified(struct DerivedMesh *);
 void multires_mark_as_modified(struct Object *ob);
 
 void multires_force_update(struct Object *ob);
@@ -64,10 +47,9 @@ struct DerivedMesh *multires_dm_create_from_derived(struct MultiresModifierData*
 						    struct Object *, int, int);
 
 struct MultiresModifierData *find_multires_modifier(struct Object *ob);
-int multiresModifier_switch_level(struct Object *, const int);
 void multiresModifier_join(struct Object *);
 void multiresModifier_del_levels(struct MultiresModifierData *, struct Object *, int direction);
-void multiresModifier_subdivide(struct MultiresModifierData *mmd, struct Object *ob, int distance,
+void multiresModifier_subdivide(struct MultiresModifierData *mmd, struct Object *ob,
 				int updateblock, int simple);
 int multiresModifier_reshape(struct MultiresModifierData *mmd, struct Object *dst, struct Object *src);
 
diff --git a/source/blender/blenkernel/intern/DerivedMesh.c b/source/blender/blenkernel/intern/DerivedMesh.c
index 5a911fcb13b..b715b1531de 100644
--- a/source/blender/blenkernel/intern/DerivedMesh.c
+++ b/source/blender/blenkernel/intern/DerivedMesh.c
@@ -1535,7 +1535,7 @@ DerivedMesh *mesh_create_derived_for_modifier(Scene *scene, Object *ob, Modifier
 	md->scene= scene;
 	
 	if (!(md->mode&eModifierMode_Realtime)) return NULL;
-	if (mti->isDisabled && mti->isDisabled(md)) return NULL;
+	if (mti->isDisabled && mti->isDisabled(md, 0)) return NULL;
 
 	if (mti->type==eModifierTypeType_OnlyDeform) {
 		int numVerts;
diff --git a/source/blender/blenkernel/intern/cdderivedmesh.c b/source/blender/blenkernel/intern/cdderivedmesh.c
index 3007564e333..b3e75549028 100644
--- a/source/blender/blenkernel/intern/cdderivedmesh.c
+++ b/source/blender/blenkernel/intern/cdderivedmesh.c
@@ -1810,215 +1810,3 @@ MFace *CDDM_get_faces(DerivedMesh *dm)
 	return ((CDDerivedMesh*)dm)->mface;
 }
 
-/* Multires DerivedMesh, extends CDDM */
-typedef struct MultiresDM {
-	CDDerivedMesh cddm;
-
-	MultiresModifierData *mmd;
-	int local_mmd;
-
-	int lvl, totlvl;
-	float (*orco)[3];
-	MVert *subco;
-
-	ListBase *vert_face_map, *vert_edge_map;
-	IndexNode *vert_face_map_mem, *vert_edge_map_mem;
-	int *face_offsets;
-
-	Object *ob;
-	int modified;
-
-	void (*update)(DerivedMesh*);
-} MultiresDM;
-
-static void MultiresDM_release(DerivedMesh *dm)
-{
-	MultiresDM *mrdm = (MultiresDM*)dm;
-	int mvert_layer;
-
-	/* Before freeing, need to update the displacement map */
-	if(dm->needsFree && mrdm->modified) {
-		/* Check that mmd still exists */
-		if(!mrdm->local_mmd && BLI_findindex(&mrdm->ob->modifiers, mrdm->mmd) < 0)
-			mrdm->mmd = NULL;
-		if(mrdm->mmd)
-			mrdm->update(dm);
-	}
-
-	/* If the MVert data is being used as the sculpt undo store, don't free it */
-	mvert_layer = CustomData_get_layer_index(&dm->vertData, CD_MVERT);
-	if(mvert_layer != -1) {
-		CustomDataLayer *cd = &dm->vertData.layers[mvert_layer];
-		if(mrdm->mmd && cd->data == mrdm->mmd->undo_verts)
-			cd->flag |= CD_FLAG_NOFREE;
-	}
-
-	if(DM_release(dm)) {
-		cdDM_free_internal(&mrdm->cddm);
-		MEM_freeN(mrdm->subco);
-		MEM_freeN(mrdm->orco);
-		if(mrdm->vert_face_map)
-			MEM_freeN(mrdm->vert_face_map);
-		if(mrdm->vert_face_map_mem)
-			MEM_freeN(mrdm->vert_face_map_mem);
-		if(mrdm->vert_edge_map)
-			MEM_freeN(mrdm->vert_edge_map);
-		if(mrdm->vert_edge_map_mem)
-			MEM_freeN(mrdm->vert_edge_map_mem);
-		if(mrdm->face_offsets)
-			MEM_freeN(mrdm->face_offsets);
-		MEM_freeN(mrdm);
-	}
-}
-
-DerivedMesh *MultiresDM_new(MultiresSubsurf *ms, DerivedMesh *orig, int numVerts, int numEdges, int numFaces)
-{
-	MultiresDM *mrdm = MEM_callocN(sizeof(MultiresDM), "MultiresDM");
-	CDDerivedMesh *cddm = cdDM_create("MultiresDM CDDM");
-	DerivedMesh *dm = NULL;
-
-	mrdm->cddm = *cddm;
-	MEM_freeN(cddm);
-	dm = &mrdm->cddm.dm;
-
-	mrdm->mmd = ms->mmd;
-	mrdm->ob = ms->ob;
-	mrdm->local_mmd = ms->local_mmd;
-
-	if(dm) {
-		MDisps *disps;
-		MVert *mvert;
-		int i;
-
-		DM_from_template(dm, orig, numVerts, numEdges, numFaces);
-		CustomData_free_layers(&dm->faceData, CD_MDISPS, numFaces);
-
-		disps = CustomData_get_layer(&orig->faceData, CD_MDISPS);
-		if(disps)
-			CustomData_add_layer(&dm->faceData, CD_MDISPS, CD_REFERENCE, disps, numFaces);
-
-
-		mvert = CustomData_get_layer(&orig->vertData, CD_MVERT);
-		mrdm->orco = MEM_callocN(sizeof(float) * 3 * orig->getNumVerts(orig), "multires orco");
-		for(i = 0; i < orig->getNumVerts(orig); ++i)
-			copy_v3_v3(mrdm->orco[i], mvert[i].co);
-	}
-	else
-		DM_init(dm, numVerts, numEdges, numFaces);
-
-	if(!CustomData_get_layer(&dm->vertData, CD_ORIGINDEX))
-		CustomData_add_layer(&dm->vertData, CD_ORIGINDEX, CD_CALLOC, NULL, numVerts);
-	if(!CustomData_get_layer(&dm->edgeData, CD_ORIGINDEX))
-		CustomData_add_layer(&dm->edgeData, CD_ORIGINDEX, CD_CALLOC, NULL, numEdges);
-	if(!CustomData_get_layer(&dm->faceData, CD_ORIGINDEX))
-		CustomData_add_layer(&dm->faceData, CD_ORIGINDEX, CD_CALLOC, NULL, numFaces);
-
-	CustomData_add_layer(&dm->vertData, CD_MVERT, CD_CALLOC, NULL, numVerts);
-	CustomData_add_layer(&dm->edgeData, CD_MEDGE, CD_CALLOC, NULL, numEdges);
-	CustomData_add_layer(&dm->faceData, CD_MFACE, CD_CALLOC, NULL, numFaces);
-
-	mrdm->cddm.mvert = CustomData_get_layer(&dm->vertData, CD_MVERT);
-	mrdm->cddm.medge = CustomData_get_layer(&dm->edgeData, CD_MEDGE);
-	mrdm->cddm.mface = CustomData_get_layer(&dm->faceData, CD_MFACE);
-
-	mrdm->lvl = ms->mmd->lvl;
-	mrdm->totlvl = ms->mmd->totlvl;
-	mrdm->subco = MEM_callocN(sizeof(MVert)*numVerts, "multires subdivided verts");
-	mrdm->modified = 0;
-
-	dm->release = MultiresDM_release;
-
-	return dm;
-}
-
-Mesh *MultiresDM_get_mesh(DerivedMesh *dm)
-{
-	return get_mesh(((MultiresDM*)dm)->ob);
-}
-
-Object *MultiresDM_get_object(DerivedMesh *dm)
-{
-	return ((MultiresDM*)dm)->ob;
-}
-
-void *MultiresDM_get_orco(DerivedMesh *dm)
-{
-	return ((MultiresDM*)dm)->orco;
-
-}
-
-MVert *MultiresDM_get_subco(DerivedMesh *dm)
-{
-	return ((MultiresDM*)dm)->subco;
-}
-
-int MultiresDM_get_totlvl(DerivedMesh *dm)
-{
-	return ((MultiresDM*)dm)->totlvl;
-}
-
-int MultiresDM_get_lvl(DerivedMesh *dm)
-{
-	return ((MultiresDM*)dm)->lvl;
-}
-
-void MultiresDM_set_orco(DerivedMesh *dm, float (*orco)[3])
-{
-	((MultiresDM*)dm)->orco = orco;
-}
-
-void MultiresDM_set_update(DerivedMesh *dm, void (*update)(DerivedMesh*))
-{
-	((MultiresDM*)dm)->update = update;
-}
-
-ListBase *MultiresDM_get_vert_face_map(DerivedMesh *dm)
-{
-	MultiresDM *mrdm = (MultiresDM*)dm;
-	Mesh *me = mrdm->ob->data;
-
-	if(!mrdm->vert_face_map)
-		create_vert_face_map(&mrdm->vert_face_map, &mrdm->vert_face_map_mem, me->mface,
-				     me->totvert, me->totface);
-
-	return mrdm->vert_face_map;
-}
-
-ListBase *MultiresDM_get_vert_edge_map(DerivedMesh *dm)
-{
-	MultiresDM *mrdm = (MultiresDM*)dm;
-	Mesh *me = mrdm->ob->data;
-
-	if(!mrdm->vert_edge_map)
-		create_vert_edge_map(&mrdm->vert_edge_map, &mrdm->vert_edge_map_mem, me->medge,
-				     me->totvert, me->totedge);
-
-	return mrdm->vert_edge_map;
-}
-
-int *MultiresDM_get_face_offsets(DerivedMesh *dm)
-{
-	MultiresDM *mrdm = (MultiresDM*)dm;
-	Mesh *me = mrdm->ob->data;
-	int i, accum = 0;
-
-	if(!mrdm->face_offsets) {
-		int len = (int)pow(2, mrdm->lvl - 2) - 1;
-		int area = len * len;
-		int t = 1 + len * 3 + area * 3, q = t + len + area;
-
-		mrdm->face_offsets = MEM_callocN(sizeof(int) * me->totface, "mrdm face offsets");
-		for(i = 0; i < me->totface; ++i) {
-			mrdm->face_offsets[i] = accum;
-
-			accum += (me->mface[i].v4 ? q : t);
-		}
-	}
-
-	return mrdm->face_offsets;
-}
-
-void MultiresDM_mark_as_modified(DerivedMesh *dm)
-{
-	((MultiresDM*)dm)->modified = 1;
-}
diff --git a/source/blender/blenkernel/intern/customdata.c b/source/blender/blenkernel/intern/customdata.c
index 7b754025b6c..4844595513f 100644
--- a/source/blender/blenkernel/intern/customdata.c
+++ b/source/blender/blenkernel/intern/customdata.c
@@ -381,6 +381,7 @@ static void layerDefault_origspace_face(void *data, int count)
 		osf[i] = default_osf;
 }
 
+#if 0
 /* Adapted from sculptmode.c */
 static void mdisps_bilinear(float out[3], float (*disps)[3], int st, float u, float v)
 {
@@ -426,9 +427,12 @@ static void mdisps_bilinear(float out[3], float (*disps)[3], int st, float u, fl
 
 	add_v3_v3v3(out, d2[0], d2[1]);
 }
+#endif
 
 static void layerSwap_mdisps(void *data, int *ci)
 {
+	// XXX
+#if 0
 	MDisps *s = data;
 	float (*d)[3] = NULL;
 	int x, y, st;
@@ -447,11 +451,14 @@ static void layerSwap_mdisps(void *data, int *ci)
 	if(s->disps)
 		MEM_freeN(s->disps);
 	s->disps = d;
+#endif
 }
 
 static void layerInterp_mdisps(void **sources, float *weights, float *sub_weights,
 			       int count, void *dest)
 {
+	// XXX
+#if 0
 	MDisps *d = dest;
 	MDisps *s = NULL;
 	int st, stl;
@@ -496,6 +503,7 @@ static void layerInterp_mdisps(void **sources, float *weights, float *sub_weight
 			copy_v3_v3(d->disps[y * st + x], srcdisp);
 		}
 	}
+#endif
 }
 
 static void layerCopy_mdisps(const void *source, void *dest, int count)
diff --git a/source/blender/blenkernel/intern/displist.c b/source/blender/blenkernel/intern/displist.c
index 48fb283c404..b35cf917895 100644
--- a/source/blender/blenkernel/intern/displist.c
+++ b/source/blender/blenkernel/intern/displist.c
@@ -1225,7 +1225,7 @@ static ModifierData *curve_get_tesselate_point(Object *ob, int forRender, int ed
 		ModifierTypeInfo *mti = modifierType_getInfo(md->type);
 
 		if ((md->mode & required_mode) != required_mode) continue;
-		if (mti->isDisabled && mti->isDisabled(md)) continue;
+		if (mti->isDisabled && mti->isDisabled(md, forRender)) continue;
 
 		if (ELEM3(md->type, eModifierType_Hook, eModifierType_Softbody, eModifierType_MeshDeform)) {
 			preTesselatePoint  = md;
@@ -1275,7 +1275,7 @@ static void curve_calc_modifiers_pre(Scene *scene, Object *ob, int forRender, fl
 			md->scene= scene;
 			
 			if ((md->mode & required_mode) != required_mode) continue;
-			if (mti->isDisabled && mti->isDisabled(md)) continue;
+			if (mti->isDisabled && mti->isDisabled(md, forRender)) continue;
 			if (mti->type!=eModifierTypeType_OnlyDeform) continue;
 
 			if (!deformedVerts) {
@@ -1330,7 +1330,7 @@ static void curve_calc_modifiers_post(Scene *scene, Object *ob, ListBase *dispba
 		md->scene= scene;
 		
 		if ((md->mode & required_mode) != required_mode) continue;
-		if (mti->isDisabled && mti->isDisabled(md)) continue;
+		if (mti->isDisabled && mti->isDisabled(md, forRender)) continue;
 		if (mti->type!=eModifierTypeType_OnlyDeform && mti->type!=eModifierTypeType_DeformOrConstruct) continue;
 
 		/* need to put all verts in 1 block for curve deform */
diff --git a/source/blender/blenkernel/intern/lattice.c b/source/blender/blenkernel/intern/lattice.c
index dc548edbb25..e963b2e9fb6 100644
--- a/source/blender/blenkernel/intern/lattice.c
+++ b/source/blender/blenkernel/intern/lattice.c
@@ -1002,7 +1002,7 @@ void lattice_calc_modifiers(Scene *scene, Object *ob)
 		
 		if (!(md->mode&eModifierMode_Realtime)) continue;
 		if (editmode && !(md->mode&eModifierMode_Editmode)) continue;
-		if (mti->isDisabled && mti->isDisabled(md)) continue;
+		if (mti->isDisabled && mti->isDisabled(md, 0)) continue;
 		if (mti->type!=eModifierTypeType_OnlyDeform) continue;
 
 		if (!vertexCos) vertexCos = lattice_getVertexCos(ob, &numVerts);
diff --git a/source/blender/blenkernel/intern/modifier.c b/source/blender/blenkernel/intern/modifier.c
index 50c907fd1ca..d8c05c30cfe 100644
--- a/source/blender/blenkernel/intern/modifier.c
+++ b/source/blender/blenkernel/intern/modifier.c
@@ -187,7 +187,7 @@ static DerivedMesh *get_original_dm(Scene *scene, Object *ob, float (*vertexCos)
 
 /***/
 
-static int noneModifier_isDisabled(ModifierData *md)
+static int noneModifier_isDisabled(ModifierData *md, int userRenderParams)
 {
 	return 1;
 }
@@ -222,7 +222,7 @@ static CustomDataMask curveModifier_requiredDataMask(Object *ob, ModifierData *m
 	return dataMask;
 }
 
-static int curveModifier_isDisabled(ModifierData *md)
+static int curveModifier_isDisabled(ModifierData *md, int userRenderParams)
 {
 	CurveModifierData *cmd = (CurveModifierData*) md;
 
@@ -298,7 +298,7 @@ static CustomDataMask latticeModifier_requiredDataMask(Object *ob, ModifierData
 	return dataMask;
 }
 
-static int latticeModifier_isDisabled(ModifierData *md)
+static int latticeModifier_isDisabled(ModifierData *md, int userRenderParams)
 {
 	LatticeModifierData *lmd = (LatticeModifierData*) md;
 
@@ -402,6 +402,13 @@ static void subsurfModifier_freeData(ModifierData *md)
 	}
 }
 
+static int subsurfModifier_isDisabled(ModifierData *md, int useRenderParams)
+{
+	SubsurfModifierData *smd = (SubsurfModifierData*) md;
+
+	return (useRenderParams)? (smd->renderLevels == 0): (smd->levels == 0);
+}
+
 static DerivedMesh *subsurfModifier_applyModifier(
 		ModifierData *md, Object *ob, DerivedMesh *derivedData,
   int useRenderParams, int isFinalCalc)
@@ -410,8 +417,13 @@ static DerivedMesh *subsurfModifier_applyModifier(
 	DerivedMesh *result;
 
 	result = subsurf_make_derived_from_derived(derivedData, smd,
-			useRenderParams, NULL,
-   isFinalCalc, 0);
+			useRenderParams, NULL, isFinalCalc, 0);
+	
+	if(useRenderParams || !isFinalCalc) {
+		DerivedMesh *cddm= CDDM_copy(result);
+		result->release(result);
+		result= cddm;
+	}
 
 	return result;
 }
@@ -3524,7 +3536,7 @@ static void displaceModifier_foreachIDLink(ModifierData *md, Object *ob,
 	displaceModifier_foreachObjectLink(md, ob, (ObjectWalkFunc)walk, userData);
 }
 
-static int displaceModifier_isDisabled(ModifierData *md)
+static int displaceModifier_isDisabled(ModifierData *md, int useRenderParams)
 {
 	DisplaceModifierData *dmd = (DisplaceModifierData*) md;
 
@@ -4268,7 +4280,7 @@ static void smoothModifier_copyData(ModifierData *md, ModifierData *target)
 	strncpy(tsmd->defgrp_name, smd->defgrp_name, 32);
 }
 
-static int smoothModifier_isDisabled(ModifierData *md)
+static int smoothModifier_isDisabled(ModifierData *md, int useRenderParams)
 {
 	SmoothModifierData *smd = (SmoothModifierData*) md;
 	short flag;
@@ -4498,7 +4510,7 @@ static void castModifier_copyData(ModifierData *md, ModifierData *target)
 	strncpy(tcmd->defgrp_name, cmd->defgrp_name, 32);
 }
 
-static int castModifier_isDisabled(ModifierData *md)
+static int castModifier_isDisabled(ModifierData *md, int useRenderParams)
 {
 	CastModifierData *cmd = (CastModifierData*) md;
 	short flag;
@@ -5487,7 +5499,7 @@ static CustomDataMask armatureModifier_requiredDataMask(Object *ob, ModifierData
 	return dataMask;
 }
 
-static int armatureModifier_isDisabled(ModifierData *md)
+static int armatureModifier_isDisabled(ModifierData *md, int useRenderParams)
 {
 	ArmatureModifierData *amd = (ArmatureModifierData*) md;
 
@@ -5610,7 +5622,7 @@ static void hookModifier_freeData(ModifierData *md)
 	if (hmd->indexar) MEM_freeN(hmd->indexar);
 }
 
-static int hookModifier_isDisabled(ModifierData *md)
+static int hookModifier_isDisabled(ModifierData *md, int useRenderParams)
 {
 	HookModifierData *hmd = (HookModifierData*) md;
 
@@ -6308,7 +6320,7 @@ static void booleanModifier_copyData(ModifierData *md, ModifierData *target)
 	tbmd->operation = bmd->operation;
 }
 
-static int booleanModifier_isDisabled(ModifierData *md)
+static int booleanModifier_isDisabled(ModifierData *md, int useRenderParams)
 {
 	BooleanModifierData *bmd = (BooleanModifierData*) md;
 
@@ -7757,7 +7769,7 @@ static CustomDataMask meshdeformModifier_requiredDataMask(Object *ob, ModifierDa
 	return dataMask;
 }
 
-static int meshdeformModifier_isDisabled(ModifierData *md)
+static int meshdeformModifier_isDisabled(ModifierData *md, int useRenderParams)
 {
 	MeshDeformModifierData *mmd = (MeshDeformModifierData*) md;
 
@@ -8047,15 +8059,10 @@ static void multiresModifier_initData(ModifierData *md)
 {
 	MultiresModifierData *mmd = (MultiresModifierData*)md;
 
-	mmd->lvl = mmd->totlvl = 1;
-}
-
-static void multiresModifier_freeData(ModifierData *md)
-{
-	MultiresModifierData *mmd = (MultiresModifierData*)md;
-
-	if(mmd->undo_verts)
-		MEM_freeN(mmd->undo_verts);
+	mmd->lvl = 0;
+	mmd->sculptlvl = 0;
+	mmd->renderlvl = 0;
+	mmd->totlvl = 0;
 }
 
 static void multiresModifier_copyData(ModifierData *md, ModifierData *target)
@@ -8063,37 +8070,35 @@ static void multiresModifier_copyData(ModifierData *md, ModifierData *target)
 	MultiresModifierData *mmd = (MultiresModifierData*) md;
 	MultiresModifierData *tmmd = (MultiresModifierData*) target;
 
-	tmmd->totlvl = mmd->totlvl;
 	tmmd->lvl = mmd->lvl;
+	tmmd->sculptlvl = mmd->sculptlvl;
+	tmmd->renderlvl = mmd->renderlvl;
+	tmmd->totlvl = mmd->totlvl;
 }
 
 static DerivedMesh *multiresModifier_applyModifier(ModifierData *md, Object *ob, DerivedMesh *dm,
 						   int useRenderParams, int isFinalCalc)
 {
 	MultiresModifierData *mmd = (MultiresModifierData*)md;
-	DerivedMesh *final;
+	DerivedMesh *result;
 
-	/* TODO: for now just skip a level1 mesh */
-	if(mmd->lvl == 1)
-		return dm;
+	result = multires_dm_create_from_derived(mmd, 0, dm, ob, useRenderParams, isFinalCalc);
 
-	final = multires_dm_create_from_derived(mmd, 0, dm, ob, useRenderParams, isFinalCalc);
-	if(mmd->undo_signal && mmd->undo_verts && mmd->undo_verts_tot == final->getNumVerts(final)) {
-		int i;
-		MVert *dst = CDDM_get_verts(final);
-		for(i = 0; i < mmd->undo_verts_tot; ++i) {
-			copy_v3_v3(dst[i].co, mmd->undo_verts[i].co);
-		}
-		CDDM_calc_normals(final);
-
-		MultiresDM_mark_as_modified(final);
+	if(result == dm)
+		return dm;
 
-		MEM_freeN(mmd->undo_verts);
-		mmd->undo_signal = 0;
-		mmd->undo_verts = NULL;
+	if(useRenderParams || !isFinalCalc) {
+		DerivedMesh *cddm= CDDM_copy(result);
+		result->release(result);
+		result= cddm;
+	}
+	else if(ob->mode & OB_MODE_SCULPT) {
+		/* would be created on the fly too, just nicer this
+		   way on first stroke after e.g. switching levels */
+		result->getPBVH(ob, result);
 	}
 
-	return final;
+	return result;
 }
 
 /* Shrinkwrap */
@@ -8142,7 +8147,7 @@ static CustomDataMask shrinkwrapModifier_requiredDataMask(Object *ob, ModifierDa
 	return dataMask;
 }
 
-static int shrinkwrapModifier_isDisabled(ModifierData *md)
+static int shrinkwrapModifier_isDisabled(ModifierData *md, int useRenderParams)
 {
 	ShrinkwrapModifierData *smd = (ShrinkwrapModifierData*) md;
 	return !smd->target;
@@ -8438,6 +8443,7 @@ ModifierTypeInfo *modifierType_getInfo(ModifierType type)
 		mti->initData = subsurfModifier_initData;
 		mti->copyData = subsurfModifier_copyData;
 		mti->freeData = subsurfModifier_freeData;
+		mti->isDisabled = subsurfModifier_isDisabled;
 		mti->applyModifier = subsurfModifier_applyModifier;
 		mti->applyModifierEM = subsurfModifier_applyModifierEM;
 
@@ -8770,7 +8776,6 @@ ModifierTypeInfo *modifierType_getInfo(ModifierType type)
 		mti->type = eModifierTypeType_Constructive;
 		mti->flags = eModifierTypeFlag_AcceptsMesh | eModifierTypeFlag_RequiresOriginalData;
 		mti->initData = multiresModifier_initData;
-		mti->freeData = multiresModifier_freeData;
 		mti->copyData = multiresModifier_copyData;
 		mti->applyModifier = multiresModifier_applyModifier;
 
@@ -8920,7 +8925,7 @@ int modifier_couldBeCage(ModifierData *md)
 
 	return (	(md->mode & eModifierMode_Realtime) &&
 			(md->mode & eModifierMode_Editmode) &&
-			(!mti->isDisabled || !mti->isDisabled(md)) &&
+			(!mti->isDisabled || !mti->isDisabled(md, 0)) &&
 			modifier_supportsMapping(md));	
 }
 
@@ -8957,7 +8962,7 @@ int modifiers_getCageIndex(Object *ob, int *lastPossibleCageIndex_r, int virtual
 
 		if (!(md->mode & eModifierMode_Realtime)) continue;
 		if (!(md->mode & eModifierMode_Editmode)) continue;
-		if (mti->isDisabled && mti->isDisabled(md)) continue;
+		if (mti->isDisabled && mti->isDisabled(md, 0)) continue;
 		if (!(mti->flags & eModifierTypeFlag_SupportsEditmode)) continue;
 		if (md->mode & eModifierMode_DisableTemporary) continue;
 
@@ -8999,7 +9004,7 @@ int modifier_isEnabled(ModifierData *md, int required_mode)
 	ModifierTypeInfo *mti = modifierType_getInfo(md->type);
 
 	if((md->mode & required_mode) != required_mode) return 0;
-	if(mti->isDisabled && mti->isDisabled(md)) return 0;
+	if(mti->isDisabled && mti->isDisabled(md, required_mode == eModifierMode_Render)) return 0;
 	if(md->mode & eModifierMode_DisableTemporary) return 0;
 	if(required_mode & eModifierMode_Editmode)
 		if(!(mti->flags & eModifierTypeFlag_SupportsEditmode)) return 0;
diff --git a/source/blender/blenkernel/intern/multires.c b/source/blender/blenkernel/intern/multires.c
index fc14afaf07f..2518d4bc3ca 100644
--- a/source/blender/blenkernel/intern/multires.c
+++ b/source/blender/blenkernel/intern/multires.c
@@ -40,6 +40,7 @@
 #include "BLI_math.h"
 #include "BLI_blenlib.h"
 
+#include "BKE_btex.h"
 #include "BKE_cdderivedmesh.h"
 #include "BKE_customdata.h"
 #include "BKE_depsgraph.h"
@@ -50,14 +51,19 @@
 #include "BKE_multires.h"
 #include "BKE_object.h"
 #include "BKE_subsurf.h"
+#include "BKE_utildefines.h"
+
+#include "CCGSubSurf.h"
 
 #include <math.h>
 #include <string.h>
 
 /* MULTIRES MODIFIER */
 static const int multires_max_levels = 13;
-static const int multires_quad_tot[] = {4, 9, 25, 81, 289, 1089, 4225, 16641, 66049, 263169, 1050625, 4198401, 16785409};
-static const int multires_side_tot[] = {2, 3, 5,  9,  17,  33,   65,   129,   257,   513,    1025,    2049,    4097};
+static const int multires_grid_tot[] = {1, 4, 9, 25, 81, 289, 1089, 4225, 16641, 66049, 263169, 1050625, 4198401, 16785409};
+static const int multires_side_tot[] = {1, 2, 3, 5,  9,  17,  33,   65,   129,   257,   513,    1025,    2049,    4097};
+
+static void multiresModifier_disp_run(DerivedMesh *dm, Mesh *me, int invert, int add, DMGridData **oldGridData, int totlvl);
 
 MultiresModifierData *find_multires_modifier(Object *ob)
 {
@@ -72,23 +78,32 @@ MultiresModifierData *find_multires_modifier(Object *ob)
 	}
 
 	return mmd;
+}
 
+static int multires_get_level(Object *ob, MultiresModifierData *mmd, int render)
+{
+	if(render)
+		return mmd->renderlvl;
+	else if(ob->mode == OB_MODE_SCULPT)
+		return mmd->sculptlvl;
+	else
+		return mmd->lvl;
 }
 
-int multiresModifier_switch_level(Object *ob, const int distance)
+static void multires_set_tot_level(Object *ob, MultiresModifierData *mmd, int lvl)
 {
-	MultiresModifierData *mmd = find_multires_modifier(ob);
-
-	if(mmd) {
-		mmd->lvl += distance;
-		if(mmd->lvl < 1) mmd->lvl = 1;
-		else if(mmd->lvl > mmd->totlvl) mmd->lvl = mmd->totlvl;
-		/* XXX: DAG_id_flush_update(&ob->id, OB_RECALC_DATA); 
-		   object_handle_update(ob);*/
-		return 1;
+	mmd->totlvl = lvl;
+
+	if(ob->mode != OB_MODE_SCULPT) {
+		mmd->lvl = MAX2(mmd->lvl, lvl);
+		CLAMP(mmd->lvl, 0, mmd->totlvl);
 	}
-	else
-		return 0;
+
+	mmd->sculptlvl = MAX2(mmd->sculptlvl, lvl);
+	CLAMP(mmd->sculptlvl, 0, mmd->totlvl);
+
+	mmd->renderlvl = MAX2(mmd->renderlvl, lvl);
+	CLAMP(mmd->renderlvl, 0, mmd->totlvl);
 }
 
 /* XXX */
@@ -156,6 +171,8 @@ void multiresModifier_join(Object *ob)
 /* Returns 0 on success, 1 if the src's totvert doesn't match */
 int multiresModifier_reshape(MultiresModifierData *mmd, Object *dst, Object *src)
 {
+	/* XXX */
+#if 0
 	Mesh *src_me = get_mesh(src);
 	DerivedMesh *mrdm = dst->derivedFinal;
 
@@ -172,319 +189,139 @@ int multiresModifier_reshape(MultiresModifierData *mmd, Object *dst, Object *src
 
 		return 0;
 	}
+#endif
 
 	return 1;
 }
 
-static void Mat3FromColVecs(float mat[][3], float v1[3], float v2[3], float v3[3])
+static void column_vectors_to_mat3(float mat[][3], float v1[3], float v2[3], float v3[3])
 {
 	copy_v3_v3(mat[0], v1);
 	copy_v3_v3(mat[1], v2);
 	copy_v3_v3(mat[2], v3);
 }
 
-static DerivedMesh *multires_subdisp_pre(DerivedMesh *mrdm, int distance, int simple)
+static void multires_copy_grid(float (*gridA)[3], float (*gridB)[3], int sizeA, int sizeB)
 {
-	DerivedMesh *final;
-	SubsurfModifierData smd;
-
-	memset(&smd, 0, sizeof(SubsurfModifierData));
-	smd.levels = distance;
-	if(simple)
-		smd.subdivType = ME_SIMPLE_SUBSURF;
+	int x, y, j, skip;
 
-	final = NULL; // XXX subsurf_make_derived_from_derived_with_multires(mrdm, &smd, NULL, 0, NULL, 0, 0);
+	if(sizeA > sizeB) {
+		skip = (sizeA-1)/(sizeB-1);
 
-	return final;
-}
+		for(j = 0, y = 0; y < sizeB; y++)
+			for(x = 0; x < sizeB; x++, j++)
+				copy_v3_v3(gridA[y*skip*sizeA + x*skip], gridB[j]);
+	}
+	else {
+		skip = (sizeB-1)/(sizeA-1);
 
-static void VecAddUf(float a[3], float b[3])
-{
-	a[0] += b[0];
-	a[1] += b[1];
-	a[2] += b[2];
+		for(j = 0, y = 0; y < sizeA; y++)
+			for(x = 0; x < sizeA; x++, j++)
+				copy_v3_v3(gridA[j], gridB[y*skip*sizeB + x*skip]);
+	}
 }
 
-static void multires_subdisp(DerivedMesh *orig, Object *ob, DerivedMesh *final, int lvl, int totlvl,
-			     int totsubvert, int totsubedge, int totsubface, int addverts)
+static void multires_copy_dm_grid(DMGridData *gridA, DMGridData *gridB, int sizeA, int sizeB)
 {
-	DerivedMesh *mrdm;
-	Mesh *me = ob->data;
-	MultiresModifierData mmd_sub;
-	MVert *mvs = CDDM_get_verts(final);
-	MVert *mvd, *mvd_f1, *mvs_f1, *mvd_f3, *mvd_f4;
-	MVert *mvd_f2, *mvs_f2, *mvs_e1, *mvd_e1, *mvs_e2;
-	int totvert;
-	int slo1 = multires_side_tot[lvl - 1];
-	int sll = slo1 / 2;
-	int slo2 = multires_side_tot[totlvl - 2];
-	int shi2 = multires_side_tot[totlvl - 1];
-	int skip = multires_side_tot[totlvl - lvl] - 1;
-	int i, j, k;
-
-	memset(&mmd_sub, 0, sizeof(MultiresModifierData));
-	mmd_sub.lvl = mmd_sub.totlvl = totlvl;
-	mrdm = multires_dm_create_from_derived(&mmd_sub, 1, orig, ob, 0, 0);
-		
-	mvd = CDDM_get_verts(mrdm);
-	/* Need to map from ccg to mrdm */
-	totvert = mrdm->getNumVerts(mrdm);
-
-	if(!addverts) {
-		for(i = 0; i < totvert; ++i) {
-			float z[3] = {0,0,0};
-			copy_v3_v3(mvd[i].co, z);
-		}
-	}
-
-	/* Load base verts */
-	for(i = 0; i < me->totvert; ++i)
-		VecAddUf(mvd[totvert - me->totvert + i].co, mvs[totvert - me->totvert + i].co);
-
-	mvd_f1 = mvd;
-	mvs_f1 = mvs;
-	mvd_f2 = mvd;
-	mvs_f2 = mvs + totvert - totsubvert;
-	mvs_e1 = mvs + totsubface * (skip-1) * (skip-1);
-
-	for(i = 0; i < me->totface; ++i) {
-		const int end = me->mface[i].v4 ? 4 : 3;
-		int x, y, x2, y2, mov= 0;
-
-		mvd_f1 += 1 + end * (slo2-2); //center+edgecross
-		mvd_f3 = mvd_f4 = mvd_f1;
-
-		for(j = 0; j < end; ++j) {
-			mvd_f1 += (skip/2 - 1) * (slo2 - 2) + (skip/2 - 1);
-			/* Update sub faces */
-			for(y = 0; y < sll; ++y) {
-				for(x = 0; x < sll; ++x) {
-					/* Face center */
-					VecAddUf(mvd_f1->co, mvs_f1->co);
-					mvs_f1 += 1;
-
-					/* Now we hold the center of the subface at mvd_f1
-					   and offset it to the edge cross and face verts */
-
-					/* Edge cross */
-					for(k = 0; k < 4; ++k) {
-						if(k == 0) mov = -1;
-						else if(k == 1) mov = slo2 - 2;
-						else if(k == 2) mov = 1;
-						else if(k == 3) mov = -(slo2 - 2);
-
-						for(x2 = 1; x2 < skip/2; ++x2) {
-							VecAddUf((mvd_f1 + mov * x2)->co, mvs_f1->co);
-							++mvs_f1;
-						}
-					}
+	int x, y, j, skip;
 
-					/* Main face verts */
-					for(k = 0; k < 4; ++k) {
-						int movx= 0, movy= 0;
-
-						if(k == 0) { movx = -1; movy = -(slo2 - 2); }
-						else if(k == 1) { movx = slo2 - 2; movy = -1; }
-						else if(k == 2) { movx = 1; movy = slo2 - 2; }
-						else if(k == 3) { movx = -(slo2 - 2); movy = 1; }
-
-						for(y2 = 1; y2 < skip/2; ++y2) {
-							for(x2 = 1; x2 < skip/2; ++x2) {
-								VecAddUf((mvd_f1 + movy * y2 + movx * x2)->co, mvs_f1->co);
-								++mvs_f1;
-							}
-						}
-					}
-							
-					mvd_f1 += skip;
-				}
-				mvd_f1 += (skip - 1) * (slo2 - 2) - 1;
-			}
-			mvd_f1 -= (skip - 1) * (slo2 - 2) - 1 + skip;
-			mvd_f1 += (slo2 - 2) * (skip/2-1) + skip/2-1 + 1;
-		}
-
-		/* update face center verts */
-		VecAddUf(mvd_f2->co, mvs_f2->co);
-
-		mvd_f2 += 1;
-		mvs_f2 += 1;
-
-		/* update face edge verts */
-		for(j = 0; j < end; ++j) {
-			MVert *restore;
-
-			/* Super-face edge cross */
-			for(k = 0; k < skip-1; ++k) {
-				VecAddUf(mvd_f2->co, mvs_e1->co);
-				mvd_f2++;
-				mvs_e1++;
-			}
-			for(x = 1; x < sll; ++x) {
-				VecAddUf(mvd_f2->co, mvs_f2->co);
-				mvd_f2++;
-				mvs_f2++;
-
-				for(k = 0; k < skip-1; ++k) {
-					VecAddUf(mvd_f2->co, mvs_e1->co);
-					mvd_f2++;
-					mvs_e1++;
-				}
-			}
-
-			restore = mvs_e1;
-			for(y = 0; y < sll - 1; ++y) {
-				for(x = 0; x < sll; ++x) {
-					for(k = 0; k < skip - 1; ++k) {
-						VecAddUf(mvd_f3[(skip-1)+(y*skip) + (x*skip+k)*(slo2-2)].co,
-							 mvs_e1->co);
-						++mvs_e1;
-					}
-					mvs_e1 += skip-1;
-				}
-			}
-			
-			mvs_e1 = restore + skip - 1;
-			for(y = 0; y < sll - 1; ++y) {
-				for(x = 0; x < sll; ++x) {
-					for(k = 0; k < skip - 1; ++k) {
-						VecAddUf(mvd_f3[(slo2-2)*(skip-1)+(x*skip)+k + y*skip*(slo2-2)].co,
-							 mvs_e1->co);
-						++mvs_e1;
-					}
-					mvs_e1 += skip - 1;
-				}
-			}
-
-			mvd_f3 += (slo2-2)*(slo2-2);
-			mvs_e1 -= skip - 1;
-		}
+	if(sizeA > sizeB) {
+		skip = (sizeA-1)/(sizeB-1);
 
-		/* update base (2) face verts */
-		for(j = 0; j < end; ++j) {
-			mvd_f2 += (slo2 - 1) * (skip - 1);
-			for(y = 0; y < sll - 1; ++y) {
-				for(x = 0; x < sll - 1; ++x) {
-					VecAddUf(mvd_f2->co, mvs_f2->co);
-					mvd_f2 += skip;
-					++mvs_f2;
-				}
-				mvd_f2 += (slo2 - 1) * (skip - 1);
-			}
-			mvd_f2 -= (skip - 1);
-		}
+		for(j = 0, y = 0; y < sizeB; y++)
+			for(x = 0; x < sizeB; x++, j++)
+				copy_v3_v3(gridA[y*skip*sizeA + x*skip].co, gridB[j].co);
 	}
+	else {
+		skip = (sizeB-1)/(sizeA-1);
 
-	/* edges */
-	mvd_e1 = mvd + totvert - me->totvert - me->totedge * (shi2-2);
-	mvs_e2 = mvs + totvert - me->totvert - me->totedge * (slo1-2);
-	for(i = 0; i < me->totedge; ++i) {
-		for(j = 0; j < skip - 1; ++j) {
-			VecAddUf(mvd_e1->co, mvs_e1->co);
-			mvd_e1++;
-			mvs_e1++;
-		}
-		for(j = 0; j < slo1 - 2; j++) {
-			VecAddUf(mvd_e1->co, mvs_e2->co);
-			mvd_e1++;
-			mvs_e2++;
-			
-			for(k = 0; k < skip - 1; ++k) {
-				VecAddUf(mvd_e1->co, mvs_e1->co);
-				mvd_e1++;
-				mvs_e1++;
-			}
-		}
+		for(j = 0, y = 0; y < sizeA; y++)
+			for(x = 0; x < sizeA; x++, j++)
+				copy_v3_v3(gridA[j].co, gridB[y*skip*sizeB + x*skip].co);
 	}
-
-	final->needsFree  = 1;
-	final->release(final);
-	mrdm->needsFree = 1;
-	MultiresDM_mark_as_modified(mrdm);
-	mrdm->release(mrdm);
 }
 
 /* direction=1 for delete higher, direction=0 for lower (not implemented yet) */
 void multiresModifier_del_levels(struct MultiresModifierData *mmd, struct Object *ob, int direction)
 {
 	Mesh *me = get_mesh(ob);
-	int distance = mmd->totlvl - mmd->lvl;
-	MDisps *mdisps = CustomData_get_layer(&me->fdata, CD_MDISPS);
+	int lvl = multires_get_level(ob, mmd, 0);
+	int levels = mmd->totlvl - lvl;
+	MDisps *mdisps;
+	
+	// XXX CustomData_external_read(&me->fdata, CD_MASK_MDISPS, me->totface);
+	mdisps= CustomData_get_layer(&me->fdata, CD_MDISPS);
 
 	multires_force_update(ob);
 
-	if(mdisps && distance > 0 && direction == 1) {
-		int skip = multires_side_tot[distance] - 1;
-		int st = multires_side_tot[mmd->totlvl - 1];
-		int totdisp = multires_quad_tot[mmd->lvl - 1];
-		int i, j, x, y;
+	if(mdisps && levels > 0 && direction == 1) {
+		int nsize = multires_side_tot[lvl];
+		int hsize = multires_side_tot[mmd->totlvl];
+		int i;
 
 		for(i = 0; i < me->totface; ++i) {
-			float (*disps)[3] = MEM_callocN(sizeof(float) * 3 * totdisp, "multires del disps");
-			
-			for(j = 0, y = 0; y < st; y += skip) {
-				for(x = 0; x < st; x += skip) {
-					copy_v3_v3(disps[j], mdisps[i].disps[y * st + x]);
-					++j;
-				}
+			MDisps *mdisp= &mdisps[i];
+			float (*disps)[3], (*ndisps)[3], (*hdisps)[3];
+			int nvert = (me->mface[i].v4)? 4: 3;
+			int totdisp = multires_grid_tot[lvl]*nvert;
+			int S;
+
+			disps = MEM_callocN(sizeof(float) * 3 * totdisp, "multires disps");
+
+			ndisps = disps;
+			hdisps = mdisp->disps;
+
+			for(S = 0; S < nvert; S++) {
+				multires_copy_grid(ndisps, hdisps, nsize, hsize);
+
+				ndisps += nsize*nsize;
+				hdisps += hsize*hsize;
 			}
 
-			MEM_freeN(mdisps[i].disps);
-			mdisps[i].disps = disps;
-			mdisps[i].totdisp = totdisp;
+			MEM_freeN(mdisp->disps);
+			mdisp->disps = disps;
+			mdisp->totdisp = totdisp;
 		}
 	}
 
-	mmd->totlvl = mmd->lvl;
+	multires_set_tot_level(ob, mmd, lvl);
 }
 
-void multiresModifier_subdivide(MultiresModifierData *mmd, Object *ob, int distance, int updateblock, int simple)
+static DerivedMesh *multires_dm_create_local(Object *ob, DerivedMesh *dm, int lvl, int totlvl, int simple)
 {
-	DerivedMesh *final = NULL;
-	int totsubvert = 0, totsubface = 0, totsubedge = 0;
-	Mesh *me = get_mesh(ob);
-	MDisps *mdisps;
-	int i;
+	MultiresModifierData mmd;
 
-	if(distance == 0)
-		return;
+	memset(&mmd, 0, sizeof(MultiresModifierData));
+	mmd.lvl = lvl;
+	mmd.sculptlvl = lvl;
+	mmd.renderlvl = lvl;
+	mmd.totlvl = totlvl;
+	mmd.simple = simple;
 
-	if(mmd->totlvl > multires_max_levels)
-		mmd->totlvl = multires_max_levels;
-	if(mmd->lvl > multires_max_levels)
-		mmd->lvl = multires_max_levels;
+	return multires_dm_create_from_derived(&mmd, 1, dm, ob, 0, 0);
+}
 
-	multires_force_update(ob);
+static DerivedMesh *subsurf_dm_create_local(Object *ob, DerivedMesh *dm, int lvl, int simple)
+{
+	SubsurfModifierData smd;
 
-	mmd->lvl = mmd->totlvl;
-	mmd->totlvl += distance;
+	memset(&smd, 0, sizeof(SubsurfModifierData));
+	smd.levels = smd.renderLevels = lvl;
+	smd.flags |= eSubsurfModifierFlag_SubsurfUv;
+	if(simple)
+		smd.subdivType = ME_SIMPLE_SUBSURF;
 
-	mdisps = CustomData_get_layer(&me->fdata, CD_MDISPS);
-	if(!mdisps)
-		mdisps = CustomData_add_layer(&me->fdata, CD_MDISPS, CD_DEFAULT, NULL, me->totface);
+	return subsurf_make_derived_from_derived(dm, &smd, 0, NULL, 0, 0);
+}
 
-	if(mdisps->disps && !updateblock && mmd->totlvl > 2) {
-		DerivedMesh *orig, *mrdm;
-		MultiresModifierData mmd_sub;
-
-		orig = CDDM_from_mesh(me, NULL);
-		memset(&mmd_sub, 0, sizeof(MultiresModifierData));
-		mmd_sub.lvl = mmd_sub.totlvl = mmd->lvl;
-		mmd_sub.simple = simple;
-		mrdm = multires_dm_create_from_derived(&mmd_sub, 1, orig, ob, 0, 0);
-		totsubvert = mrdm->getNumVerts(mrdm);
-		totsubedge = mrdm->getNumEdges(mrdm);
-		totsubface = mrdm->getNumFaces(mrdm);
-		orig->needsFree = 1;
-		orig->release(orig);
-		
-		final = multires_subdisp_pre(mrdm, distance, simple);
-		mrdm->needsFree = 1;
-		mrdm->release(mrdm);
-	}
+static void multires_reallocate_mdisps(Mesh *me, MDisps *mdisps, int lvl)
+{
+	int i;
 
+	/* reallocate displacements to be filled in */
 	for(i = 0; i < me->totface; ++i) {
-		const int totdisp = multires_quad_tot[mmd->totlvl - 1];
+		int nvert = (me->mface[i].v4)? 4: 3;
+		int totdisp = multires_grid_tot[lvl]*nvert;
 		float (*disps)[3] = MEM_callocN(sizeof(float) * 3 * totdisp, "multires disps");
 
 		if(mdisps[i].disps)
@@ -493,732 +330,353 @@ void multiresModifier_subdivide(MultiresModifierData *mmd, Object *ob, int dista
 		mdisps[i].disps = disps;
 		mdisps[i].totdisp = totdisp;
 	}
-
-
-	if(final) {
-		DerivedMesh *orig;
-
-		orig = CDDM_from_mesh(me, NULL);
-
-		multires_subdisp(orig, ob, final, mmd->lvl, mmd->totlvl, totsubvert, totsubedge, totsubface, 0);
-
-		orig->needsFree = 1;
-		orig->release(orig);
-	}
-
-	mmd->lvl = mmd->totlvl;
 }
 
-typedef struct DisplacerEdges {
-	/* DerivedMesh index at the start of each edge (using face x/y directions to define the start) */
-	int base[4];
-	/* 1 if edge moves in the positive x or y direction, -1 otherwise */
-	int dir[4];
-} DisplacerEdges;
-
-typedef struct DisplacerSpill {
-	/* Index of face (in base mesh), -1 for none */
-	int face;
-
-	/* Spill flag */
-	/* 1 = Negative variable axis */
-	/* 2 = Near fixed axis */
-	/* 4 = Flip axes */
-	int f;
-
-	/* Neighboring edges */
-	DisplacerEdges edges;
-} DisplacerSpill;
-
-typedef struct MultiresDisplacer {
-	Mesh *me;
-	MDisps *grid;
-	MFace *face;
-	
-	int dm_first_base_vert_index;
-
-	int spacing;
-	int sidetot, interior_st, disp_st;
-	int sidendx;
-	int type;
-	int invert;
-	MVert *subco;
-	int subco_index, face_index;
-	float weight;
-
-	/* Valence for each corner */
-	int valence[4];
-
-	/* Neighboring edges for current face */
-	DisplacerEdges edges_primary;
-
-	/* Neighboring faces */
-	DisplacerSpill spill_x, spill_y;
-
-	int *face_offsets;
-
-	int x, y, ax, ay;
-} MultiresDisplacer;
-
-static int mface_v(MFace *f, int v)
+void multiresModifier_subdivide(MultiresModifierData *mmd, Object *ob, int updateblock, int simple)
 {
-	return v == 0 ? f->v1 : v == 1 ? f->v2 : v == 2 ? f->v3 : v == 3 ? f->v4 : -1;
-}
+	Mesh *me = ob->data;
+	MDisps *mdisps;
+	int lvl= mmd->totlvl;
+	int totlvl= mmd->totlvl+1;
 
-/* Get the edges (and their directions) */
-static void find_displacer_edges(MultiresDisplacer *d, DerivedMesh *dm, DisplacerEdges *de, MFace *f)
-{
-	ListBase *emap = MultiresDM_get_vert_edge_map(dm);
-	IndexNode *n;
-	int i, end = f->v4 ? 4 : 3;
-	int offset = dm->getNumVerts(dm) - d->me->totvert - d->me->totedge * d->interior_st;
+	if(totlvl > multires_max_levels)
+		return;
 
-	for(i = 0; i < end; ++i) {
-		int vcur = mface_v(f, i);
-		int vnext = mface_v(f, i == end - 1 ? 0 : i + 1);
+	multires_force_update(ob);
 
-		de->dir[i] = 1;
-		
-		for(n = emap[vcur].first; n; n = n->next) {
-			MEdge *e = &d->me->medge[n->index];
-			
-			if(e->v1 == vnext || e->v2 == vnext) {
-				de->base[i] = n->index * d->interior_st;
-				if(((i == 0 || i == 1) && e->v1 == vnext) ||
-				   ((i == 2 || i == 3) && e->v2 == vnext)) {
-					de->dir[i] = -1;
-					de->base[i] += d->interior_st - 1;
-				}
-				de->base[i] += offset;
-				break;
-			}
-		}
-	}
-}
+	mdisps = CustomData_get_layer(&me->fdata, CD_MDISPS);
+	if(!mdisps)
+		mdisps = CustomData_add_layer(&me->fdata, CD_MDISPS, CD_DEFAULT, NULL, me->totface);
 
-/* Returns in out the corners [0-3] that use v1 and v2 */
-static void find_face_corners(MFace *f, int v1, int v2, int out[2])
-{
-	int i, end = f->v4 ? 4 : 3;
-
-	for(i = 0; i < end; ++i) {
-		int corner = mface_v(f, i);
-		if(corner == v1)
-			out[0] = i;
-		if(corner == v2)
-			out[1] = i;
-	}
-}
+	if(mdisps->disps && !updateblock && totlvl > 1) {
+		/* upsample */
+		DerivedMesh *lowdm, *cddm, *highdm;
+		DMGridData **highGridData, **lowGridData, **subGridData;
+		CCGSubSurf *ss;
+		int i, numGrids, highGridSize, lowGridSize;
+
+		/* create subsurf DM from original mesh at high level */
+		cddm = CDDM_from_mesh(me, NULL);
+		highdm = subsurf_dm_create_local(ob, cddm, totlvl, simple);
+
+		/* create multires DM from original mesh at low level */
+		lowdm = multires_dm_create_local(ob, cddm, lvl, lvl, simple);
+		cddm->release(cddm);
+
+		/* copy subsurf grids and replace them with low displaced grids */
+		numGrids = highdm->getNumGrids(highdm);
+		highGridSize = highdm->getGridSize(highdm);
+		highGridData = highdm->getGridData(highdm);
+		lowGridSize = lowdm->getGridSize(lowdm);
+		lowGridData = lowdm->getGridData(lowdm);
+
+		subGridData = MEM_callocN(sizeof(float*)*numGrids, "subGridData*");
+
+		for(i = 0; i < numGrids; ++i) {
+			/* backup subsurf grids */
+			subGridData[i] = MEM_callocN(sizeof(DMGridData)*highGridSize*highGridSize, "subGridData");
+			memcpy(subGridData[i], highGridData[i], sizeof(DMGridData)*highGridSize*highGridSize);
+
+			/* overwrite with current displaced grids */
+			multires_copy_dm_grid(highGridData[i], lowGridData[i], highGridSize, lowGridSize);
+		}
 
-static void multires_displacer_get_spill_faces(MultiresDisplacer *d, DerivedMesh *dm, MFace *mface)
-{
-	ListBase *map = MultiresDM_get_vert_face_map(dm);
-	IndexNode *n1, *n2;
-	int v4 = d->face->v4 ? d->face->v4 : d->face->v1;
-	int crn[2], lv;
+		/* low lower level dm no longer needed at this point */
+		lowdm->release(lowdm);
 
-	memset(&d->spill_x, 0, sizeof(DisplacerSpill));
-	memset(&d->spill_y, 0, sizeof(DisplacerSpill));
-	d->spill_x.face = d->spill_y.face = -1;
+		/* subsurf higher levels again with displaced data */
+		ss= ((CCGDerivedMesh*)highdm)->ss;
+		ccgSubSurf_updateFromFaces(ss, lvl, NULL, 0);
+		ccgSubSurf_updateLevels(ss, lvl, NULL, 0);
 
-	for(n1 = map[d->face->v3].first; n1; n1 = n1->next) {
-		if(n1->index == d->face_index)
-			continue;
+		/* reallocate displacements */
+		multires_reallocate_mdisps(me, mdisps, totlvl); 
 
-		for(n2 = map[d->face->v2].first; n2; n2 = n2->next) {
-			if(n1->index == n2->index)
-				d->spill_x.face = n1->index;
-		}
-		for(n2 = map[v4].first; n2; n2 = n2->next) {
-			if(n1->index == n2->index)
-				d->spill_y.face = n1->index;
-		}
-	}
+		/* compute displacements */
+		multiresModifier_disp_run(highdm, me, 1, 0, subGridData, totlvl);
 
-	if(d->spill_x.face != -1) {
-		/* Neighbor of v2/v3 found, find flip and orientation */
-		find_face_corners(&mface[d->spill_x.face], d->face->v2, d->face->v3, crn);
-		lv = mface[d->spill_x.face].v4 ? 3 : 2;
-
-		if(crn[0] == 0 && crn[1] == lv)
-			d->spill_x.f = 0+2+0;
-		else if(crn[0] == lv && crn[1] == 0)
-			d->spill_x.f = 1+2+0;
-		else if(crn[0] == 1 && crn[1] == 0)
-			d->spill_x.f = 1+2+4;
-		else if(crn[0] == 0 && crn[1] == 1)
-			d->spill_x.f = 0+2+4;
-		else if(crn[0] == 2 && crn[1] == 1)
-			d->spill_x.f = 1+0+0;
-		else if(crn[0] == 1 && crn[1] == 2)
-			d->spill_x.f = 0+0+0;
-		else if(crn[0] == 3 && crn[1] == 2)
-			d->spill_x.f = 0+0+4;
-		else if(crn[0] == 2 && crn[1] == 3)
-			d->spill_x.f = 1+0+4;
-
-		find_displacer_edges(d, dm, &d->spill_x.edges, &mface[d->spill_x.face]);
+		/* free */
+		highdm->release(highdm);
+		for(i = 0; i < numGrids; ++i)
+			MEM_freeN(subGridData[i]);
+		MEM_freeN(subGridData);
 	}
-
-	if(d->spill_y.face != -1) {
-		/* Neighbor of v3/v4 found, find flip and orientation */
-		find_face_corners(&mface[d->spill_y.face], d->face->v3, v4, crn);
-		lv = mface[d->spill_y.face].v4 ? 3 : 2;
-
-		if(crn[0] == 1 && crn[1] == 0)
-			d->spill_y.f = 1+2+0;
-		else if(crn[0] == 0 && crn[1] == 1)
-			d->spill_y.f = 0+2+0;
-		else if(crn[0] == 2 && crn[1] == 1)
-			d->spill_y.f = 1+0+4;
-		else if(crn[0] == 1 && crn[1] == 2)
-			d->spill_y.f = 0+0+4;
-		else if(crn[0] == 3 && crn[1] == 2)
-			d->spill_y.f = 0+0+0;
-		else if(crn[0] == 2 && crn[1] == 3)
-			d->spill_y.f = 1+0+0;
-		else if(crn[0] == 0 && crn[1] == lv)
-			d->spill_y.f = 0+2+4;
-		else if(crn[0] == lv && crn[1] == 0)
-			d->spill_y.f = 1+2+4;
-
-		find_displacer_edges(d, dm, &d->spill_y.edges, &mface[d->spill_y.face]);
+	else {
+		/* only reallocate, nothing to upsample */
+		multires_reallocate_mdisps(me, mdisps, totlvl); 
 	}
-}
-
-static void find_corner_valences(MultiresDisplacer *d, DerivedMesh *dm)
-{
-	int i;
-
-	d->valence[3] = -1;
 
-	/* Set the vertex valence for the corners */
-	for(i = 0; i < (d->face->v4 ? 4 : 3); ++i)
-		d->valence[i] = BLI_countlist(&MultiresDM_get_vert_edge_map(dm)[mface_v(d->face, i)]);
+	multires_set_tot_level(ob, mmd, totlvl);
 }
 
-static void multires_displacer_init(MultiresDisplacer *d, DerivedMesh *dm,
-			     const int face_index, const int invert)
+static void grid_adjacent_rotate(int rotation, int gridSize, int *x, int *y)
 {
-	Mesh *me = MultiresDM_get_mesh(dm);
-
-	d->me = me;
-	d->face = me->mface + face_index;
-	d->face_index = face_index;
-	d->face_offsets = MultiresDM_get_face_offsets(dm);
-	/* Get the multires grid from customdata */
-	d->grid = CustomData_get_layer(&me->fdata, CD_MDISPS);
-	if(d->grid)
-		d->grid += face_index;
-
-	d->spacing = pow(2, MultiresDM_get_totlvl(dm) - MultiresDM_get_lvl(dm));
-	d->sidetot = multires_side_tot[MultiresDM_get_lvl(dm) - 1];
-	d->interior_st = d->sidetot - 2;
-	d->disp_st = multires_side_tot[MultiresDM_get_totlvl(dm) - 1];
-	d->invert = invert;
-
-	multires_displacer_get_spill_faces(d, dm, me->mface);
-	find_displacer_edges(d, dm, &d->edges_primary, d->face);
-	find_corner_valences(d, dm);
-
-	d->dm_first_base_vert_index = dm->getNumVerts(dm) - me->totvert;
-}
+	/* we rotate (rotation * 90°) counterclockwise around center */
+	int nx, ny;
+
+	switch(rotation) {
+		case 0: nx = *x; ny = *y; break;
+		case 1: nx = *y; ny = *x; break;
+		case 2: nx = *x; ny = *y; break; //gridSize - 1 - *x; ny = gridSize - 1 - *y; break;
+		case 3: nx = *y; ny = *x; break;
+	}
 
-static void multires_displacer_weight(MultiresDisplacer *d, const float w)
-{
-	d->weight = w;
+	*x = nx;
+	*y = ny;
 }
 
-static void multires_displacer_anchor(MultiresDisplacer *d, const int type, const int side_index)
+static void grid_adjacent_jump(DMGridAdjacency *adj, int gridSize, int *index, int *x, int *y)
 {
-	d->sidendx = side_index;
-	d->x = d->y = d->sidetot / 2;
-	d->type = type;
-
-	if(type == 2) {
-		if(side_index == 0)
-			d->y -= 1;
-		else if(side_index == 1)
-			d->x += 1;
-		else if(side_index == 2)
-			d->y += 1;
-		else if(side_index == 3)
-			d->x -= 1;
-	}
-	else if(type == 3) {
-		if(side_index == 0) {
-			d->x -= 1;
-			d->y -= 1;
+	if(*x < 0) {
+		if(adj->index[3] == -1) {
+			/* no adjacent grid, clamp */
+			*x = 0;
 		}
-		else if(side_index == 1) {
-			d->x += 1;
-			d->y -= 1;
+		else {
+			/* jump to adjacent grid */
+			*index = adj->index[3];
+			*x += gridSize;
+			grid_adjacent_rotate(adj->rotation[3], gridSize, x, y);
 		}
-		else if(side_index == 2) {
-			d->x += 1;
-			d->y += 1;
+	}
+	else if(*x >= gridSize) {
+		if(adj->index[1] == -1) {
+			/* no adjacent grid, take a step back */
+			*x = gridSize - 1;
 		}
-		else if(side_index == 3) {
-			d->x -= 1;
-			d->y += 1;
+		else {
+			/* jump to adjacent grid */
+			*index = adj->index[1];
+			*x -= gridSize;
+			grid_adjacent_rotate(adj->rotation[1], gridSize, x, y);
 		}
 	}
-
-	d->ax = d->x;
-	d->ay = d->y;
-}
-
-static void multires_displacer_anchor_edge(MultiresDisplacer *d, int v1, int v2, int x)
-{
-	d->type = 4;
-
-	if(v1 == d->face->v1) {
-		d->x = 0;
-		d->y = 0;
-		if(v2 == d->face->v2)
-			d->x += x;
-		else if(v2 == d->face->v3) {
-			if(x < d->sidetot / 2)
-				d->y = x;
-			else {
-				d->x = x;
-				d->y = d->sidetot - 1;
-			}
+	else if(*y < 0) {
+		if(adj->index[0] == -1) {
+			/* no adjacent grid, clamp */
+			*y = 0;
 		}
-		else
-			d->y += x;
-	}
-	else if(v1 == d->face->v2) {
-		d->x = d->sidetot - 1;
-		d->y = 0;
-		if(v2 == d->face->v1)
-			d->x -= x;
-		else
-			d->y += x;
-	}
-	else if(v1 == d->face->v3) {
-		d->x = d->sidetot - 1;
-		d->y = d->sidetot - 1;
-		if(v2 == d->face->v2)
-			d->y -= x;
-		else if(v2 == d->face->v1) {
-			if(x < d->sidetot / 2)
-				d->x -= x;
-			else {
-				d->x = 0;
-				d->y -= x;
-			}
+		else {
+			/* jump to adjacent grid */
+			*index = adj->index[0];
+			*y += gridSize;
+			grid_adjacent_rotate(adj->rotation[0], gridSize, x, y);
 		}
-		else
-			d->x -= x;
 	}
-	else if(v1 == d->face->v4) {
-		d->x = 0;
-		d->y = d->sidetot - 1;
-		if(v2 == d->face->v3)
-			d->x += x;
-		else
-			d->y -= x;
+	else if(*y >= gridSize) {
+		if(adj->index[2] == -1) {
+			/* no adjacent grid, take a step back */
+			*y = gridSize - 1;
+		}
+		else {
+			/* jump to adjacent grid */
+			*index = adj->index[2];
+			*y -= gridSize;
+			grid_adjacent_rotate(adj->rotation[2], gridSize, x, y);
+		}
 	}
 }
 
-static void multires_displacer_anchor_vert(MultiresDisplacer *d, const int v)
-{
-	const int e = d->sidetot - 1;
-
-	d->type = 5;
-
-	d->x = d->y = 0;
-	if(v == d->face->v2)
-		d->x = e;
-	else if(v == d->face->v3)
-		d->x = d->y = e;
-	else if(v == d->face->v4)
-		d->y = e;
-}
-
-static void multires_displacer_jump(MultiresDisplacer *d)
+static void grid_tangent(DMGridAdjacency *adj, int gridSize, int index, int x, int y, int axis, DMGridData **gridData, float t[3])
 {
-	if(d->sidendx == 0) {
-		d->x -= 1;
-		d->y = d->ay;
-	}
-	else if(d->sidendx == 1) {
-		d->x = d->ax;
-		d->y -= 1;
-	}
-	else if(d->sidendx == 2) {
-		d->x += 1;
-		d->y = d->ay;
-	}
-	else if(d->sidendx == 3) {
-		d->x = d->ax;
-		d->y += 1;
+	int jindex = index, jx = x, jy = y;
+
+	if(axis == 0) {
+		if(adj->index[1] == -1 && x == gridSize - 1) {
+			if(adj->index[2] == -1 && y == gridSize - 1)
+				sub_v3_v3v3(t, gridData[index][x + gridSize*(y - 1)].co, gridData[index][x - 1 + gridSize*(y - 1)].co);
+			else
+				sub_v3_v3v3(t, gridData[index][x + gridSize*y].co, gridData[index][x - 1 + gridSize*y].co);
+		}
+		else {
+			jx += 1;
+			grid_adjacent_jump(adj, gridSize, &jindex, &jx, &jy);
+			sub_v3_v3v3(t, gridData[jindex][jx + gridSize*jy].co, gridData[index][x + gridSize*y].co);
+		}
 	}
-}
-
-/* Treating v1 as (0,0) and v3 as (st-1,st-1),
-   returns the index of the vertex at (x,y).
-   If x or y is >= st, wraps over to the adjacent face,
-   or if there is no adjacent face, returns -2. */
-static int multires_index_at_loc(int face_index, int x, int y, MultiresDisplacer *d, DisplacerEdges *de)
-{
-	int coord_edge = d->sidetot - 1; /* Max value of x/y at edge of grid */
-	int mid = d->sidetot / 2;
-	int lim = mid - 1;
-	int qtot = lim * lim;
-	int base = d->face_offsets[face_index];
- 
-	/* Edge spillover */
-	if(x == d->sidetot || y == d->sidetot) {
-		int flags, v_axis, f_axis, lx, ly;
-
-		if(x == d->sidetot && d->spill_x.face != -1) {
-			flags = d->spill_x.f;
-
-			/* Handle triangle seam between v1 and v3 */
-			if(!d->me->mface[d->spill_x.face].v4 &&
-			   ((flags == 2 && y >= mid) || (flags == 3 && y < mid)))
-				flags += 2;
-
-			v_axis = (flags & 1) ? d->sidetot - 1 - y : y;
-			f_axis = (flags & 2) ? 1 : d->sidetot - 2;
-			lx = f_axis, ly = v_axis;
-
-			if(flags & 4) {
-				lx = v_axis;
-				ly = f_axis;
+	else if(axis == 1) {
+		if(adj->index[2] == -1 && y == gridSize - 1) {
+			if(adj->index[1] == -1 && x == gridSize - 1) {
+				sub_v3_v3v3(t, gridData[index][x - 1 + gridSize*y].co, gridData[index][x - 1 + gridSize*(y - 1)].co);
 			}
-
-			return multires_index_at_loc(d->spill_x.face, lx, ly, d, &d->spill_x.edges);
-		}
-		else if(y == d->sidetot && d->spill_y.face != -1) {
-			flags = d->spill_y.f;
-
-			/* Handle triangle seam between v1 and v3 */
-			if(!d->me->mface[d->spill_y.face].v4 &&
-			   ((flags == 6 && x >= mid) || (flags == 7 && x < mid)))
-				flags = ~flags;
-
-			v_axis = (flags & 1) ? x : d->sidetot - 1 - x;
-			f_axis = (flags & 2) ? 1 : d->sidetot - 2;
-			lx = v_axis, ly = f_axis;
-
-			if(flags & 4) {
-				lx = f_axis;
-				ly = v_axis;
+			else {
+				sub_v3_v3v3(t, gridData[index][x + gridSize*y].co, gridData[index][x + gridSize*(y - 1)].co);
 			}
-			
-			return multires_index_at_loc(d->spill_y.face, lx, ly, d, &d->spill_y.edges);
 		}
-		else
-			return -2;
-	}
-	/* Corners */
-	else if(x == 0 && y == 0)
-		return d->dm_first_base_vert_index + d->face->v1;
-	else if(x == coord_edge && y == 0)
-		return d->dm_first_base_vert_index + d->face->v2;
-	else if(x == coord_edge && y == coord_edge)
-		return d->dm_first_base_vert_index + d->face->v3;
-	else if(x == 0 && y == coord_edge)
-		return d->dm_first_base_vert_index + d->face->v4;
-	/* Edges */
-	else if(x == 0) {
-		if(d->face->v4)
-			return de->base[3] + de->dir[3] * (y - 1);
-		else
-			return de->base[2] + de->dir[2] * (y - 1);
-	}
-	else if(y == 0)
-		return de->base[0] + de->dir[0] * (x - 1);
-	else if(x == d->sidetot - 1)
-		return de->base[1] + de->dir[1] * (y - 1);
-	else if(y == d->sidetot - 1)
-		return de->base[2] + de->dir[2] * (x - 1);
-	/* Face center */
-	else if(x == mid && y == mid)
-		return base;
-	/* Cross */
-	else if(x == mid && y < mid)
-		return base + (mid - y);
-	else if(y == mid && x > mid)
-		return base + lim + (x - mid);
-	else if(x == mid && y > mid)
-		return base + lim*2 + (y - mid);
-	else if(y == mid && x < mid) {
-		if(d->face->v4)
-			return base + lim*3 + (mid - x);
-		else
-			return base + lim*2 + (mid - x);
-	}
-	/* Quarters */
-	else {
-		int offset = base + lim * (d->face->v4 ? 4 : 3);
-		if(x < mid && y < mid)
-			return offset + ((mid - x - 1)*lim + (mid - y));
-		else if(x > mid && y < mid)
-			return offset + qtot + ((mid - y - 1)*lim + (x - mid));
-		else if(x > mid && y > mid)
-			return offset + qtot*2 + ((x - mid - 1)*lim + (y - mid));
-		else if(x < mid && y > mid)
-			return offset + qtot*3 + ((y - mid - 1)*lim + (mid - x));
-	}
-		
-	return -1;
-}
-
-/* Calculate the TS matrix used for applying displacements.
-   Uses the undisplaced subdivided mesh's curvature to find a
-   smoothly normal and tangents. */
-static void calc_disp_mat(MultiresDisplacer *d, float mat[3][3])
-{
-	int u = multires_index_at_loc(d->face_index, d->x + 1, d->y, d, &d->edges_primary);
-	int v = multires_index_at_loc(d->face_index, d->x, d->y + 1, d, &d->edges_primary);
-	float norm[3], t1[3], t2[3], inv[3][3];
-	MVert *base = d->subco + d->subco_index;
-
-	//printf("f=%d, x=%d, y=%d, i=%d, u=%d, v=%d ", d->face_index, d->x, d->y, d->subco_index, u, v);
-	
-	norm[0] = base->no[0] / 32767.0f;
-	norm[1] = base->no[1] / 32767.0f;
-	norm[2] = base->no[2] / 32767.0f;
-
-	/* Special handling for vertices of valence 3 */
-	if(d->valence[1] == 3 && d->x == d->sidetot - 1 && d->y == 0)
-		u = -1;
-	else if(d->valence[2] == 3 && d->x == d->sidetot - 1 && d->y == d->sidetot - 1)
-		u = v = -1;
-	else if(d->valence[3] == 3 && d->x == 0 && d->y == d->sidetot - 1)
-		v = -1;
-
-	/* If either u or v is -2, it's on a boundary. In this
-	   case, back up by one row/column and use the same
-	   vector as the preceeding sub-edge. */
-
-	if(u < 0) {
-		u = multires_index_at_loc(d->face_index, d->x - 1, d->y, d, &d->edges_primary);
-		sub_v3_v3v3(t1, base->co, d->subco[u].co);
-	}
-	else
-		sub_v3_v3v3(t1, d->subco[u].co, base->co);
-
-	if(v < 0) {
-		v = multires_index_at_loc(d->face_index, d->x, d->y - 1, d, &d->edges_primary);
-		sub_v3_v3v3(t2, base->co, d->subco[v].co);
-	}
-	else
-		sub_v3_v3v3(t2, d->subco[v].co, base->co);
-
-	//printf("uu=%d, vv=%d\n", u, v);
-
-	normalize_v3(t1);
-	normalize_v3(t2);
-	Mat3FromColVecs(mat, t1, t2, norm);
-
-	if(d->invert) {
-		invert_m3_m3(inv, mat);
-		copy_m3_m3(mat, inv);
+		else {
+			jy += 1;
+			grid_adjacent_jump(adj, gridSize, &jindex, &jx, &jy);
+			sub_v3_v3v3(t, gridData[jindex][jx + gridSize*jy].co, gridData[index][x + gridSize*y].co);
+		}
 	}
 }
 
-static void multires_displace(MultiresDisplacer *d, float co[3])
+static void multiresModifier_disp_run(DerivedMesh *dm, Mesh *me, int invert, int add, DMGridData **oldGridData, int totlvl)
 {
-	float disp[3], mat[3][3];
-	float *data;
-	MVert *subco = &d->subco[d->subco_index];
-
-	if(!d->grid || !d->grid->disps) return;
-
-	data = d->grid->disps[(d->y * d->spacing) * d->disp_st + (d->x * d->spacing)];
-
-	if(d->invert)
-		sub_v3_v3v3(disp, co, subco->co);
-	else
-		copy_v3_v3(disp, data);
-
-
-	/* Apply ts matrix to displacement */
-	calc_disp_mat(d, mat);
-	mul_m3_v3(mat, disp);
-
-	if(d->invert) {
-		copy_v3_v3(data, disp);
-		
-	}
-	else {
-		if(d->type == 4 || d->type == 5)
-			mul_v3_fl(disp, d->weight);
-		add_v3_v3v3(co, co, disp);
-	}
+	CCGDerivedMesh *ccgdm = (CCGDerivedMesh*)dm;
+	DMGridData **gridData, **subGridData;
+	DMGridAdjacency *gridAdjacency;
+	MFace *mface = me->mface;
+	MDisps *mdisps = CustomData_get_layer(&me->fdata, CD_MDISPS);
+	int i, S, x, y, numGrids, gIndex, gridSize, dGridSize, dSkip;
 
-	if(d->type == 2) {
-		if(d->sidendx == 0)
-			d->y -= 1;
-		else if(d->sidendx == 1)
-			d->x += 1;
-		else if(d->sidendx == 2)
-			d->y += 1;
-		else if(d->sidendx == 3)
-			d->x -= 1;
-	}
-	else if(d->type == 3) {
-		if(d->sidendx == 0)
-			d->y -= 1;
-		else if(d->sidendx == 1)
-			d->x += 1;
-		else if(d->sidendx == 2)
-			d->y += 1;
-		else if(d->sidendx == 3)
-			d->x -= 1;
-	}
-}
+	numGrids = dm->getNumGrids(dm);
+	gridSize = dm->getGridSize(dm);
+	gridData = dm->getGridData(dm);
+	gridAdjacency = dm->getGridAdjacency(dm);
+	subGridData = (oldGridData)? oldGridData: gridData;
 
-static void multiresModifier_disp_run(DerivedMesh *dm, MVert *subco, int invert)
-{
-	const int lvl = MultiresDM_get_lvl(dm);
-	const int gridFaces = multires_side_tot[lvl - 2] - 1;
-	const int edgeSize = multires_side_tot[lvl - 1] - 1;
-	MVert *mvert = CDDM_get_verts(dm);
-	MEdge *medge = MultiresDM_get_mesh(dm)->medge;
-	MFace *mface = MultiresDM_get_mesh(dm)->mface;
-	ListBase *map = MultiresDM_get_vert_face_map(dm);
-	Mesh *me = MultiresDM_get_mesh(dm);
-	MultiresDisplacer d;
-	int i, S, x, y;
-
-	d.subco = subco;
-	d.subco_index = 0;
+	dGridSize = multires_side_tot[totlvl];
+	dSkip = (dGridSize-1)/(gridSize-1);
 
-	for(i = 0; i < me->totface; ++i) {
+	for(gIndex = 0, i = 0; i < me->totface; ++i) {
 		const int numVerts = mface[i].v4 ? 4 : 3;
-		
-		/* Center */
-		multires_displacer_init(&d, dm, i, invert);
-		multires_displacer_anchor(&d, 1, 0);
-		multires_displace(&d, mvert->co);
-		++mvert;
-		++d.subco_index;
-
-		/* Cross */
-		for(S = 0; S < numVerts; ++S) {
-			multires_displacer_anchor(&d, 2, S);
-			for(x = 1; x < gridFaces; ++x) {
-				multires_displace(&d, mvert->co);
-				++mvert;
-				++d.subco_index;
-			}
-		}
-
-		/* Quarters */
-		for(S = 0; S < numVerts; S++) {
-			multires_displacer_anchor(&d, 3, S);
-			for(y = 1; y < gridFaces; y++) {
-				for(x = 1; x < gridFaces; x++) {
-					multires_displace(&d, mvert->co);
-					++mvert;
-					++d.subco_index;
-				}
-				multires_displacer_jump(&d);
-			}
-		}
-	}
-
-	for(i = 0; i < me->totedge; ++i) {
-		const MEdge *e = &medge[i];
-		for(x = 1; x < edgeSize; ++x) {
-			IndexNode *n1, *n2;
-			int numFaces = 0;
-			for(n1 = map[e->v1].first; n1; n1 = n1->next) {
-				for(n2 = map[e->v2].first; n2; n2 = n2->next) {
-					if(n1->index == n2->index)
-						++numFaces;
-				}
-			}
-			multires_displacer_weight(&d, 1.0f / numFaces);
-			/* TODO: Better to have these loops outside the x loop */
-			for(n1 = map[e->v1].first; n1; n1 = n1->next) {
-				for(n2 = map[e->v2].first; n2; n2 = n2->next) {
-					if(n1->index == n2->index) {
-						multires_displacer_init(&d, dm, n1->index, invert);
-						multires_displacer_anchor_edge(&d, e->v1, e->v2, x);
-						multires_displace(&d, mvert->co);
+		MDisps *mdisp = &mdisps[i];
+
+		for(S = 0; S < numVerts; ++S, ++gIndex) {
+			DMGridData *grid = gridData[gIndex];
+			DMGridData *subgrid = subGridData[gIndex];
+			DMGridAdjacency *adj = &gridAdjacency[gIndex];
+			float (*dispgrid)[3] = &mdisp->disps[S*dGridSize*dGridSize];
+
+			for(y = 0; y < gridSize; y++) {
+				for(x = 0; x < gridSize; x++) {
+					float *co = grid[x + y*gridSize].co;
+					float *sco = subgrid[x + y*gridSize].co;
+					float *no = subgrid[x + y*gridSize].no;
+					float *data = dispgrid[dGridSize*y*dSkip + x*dSkip];
+					float mat[3][3], tx[3], ty[3], disp[3], d[3];
+
+					/* construct tangent space matrix */
+					grid_tangent(adj, gridSize, gIndex, x, y, 0, subGridData, tx);
+					normalize_v3(tx);
+
+					grid_tangent(adj, gridSize, gIndex, x, y, 1, subGridData, ty);
+					normalize_v3(ty);
+
+					column_vectors_to_mat3(mat, tx, ty, no);
+
+					if(!invert) {
+						/* convert to object space and add */
+						mul_v3_m3v3(disp, mat, data);
+						add_v3_v3v3(co, sco, disp);
+					}
+					else if(!add) {
+						/* convert difference to tangent space */
+						sub_v3_v3v3(disp, co, sco);
+						invert_m3(mat);
+						mul_v3_m3v3(data, mat, disp);
+					}
+					else {
+						/* convert difference to tangent space */
+						invert_m3(mat);
+						mul_v3_m3v3(d, mat, co);
+						add_v3_v3(data, d);
 					}
 				}
 			}
-			++mvert;
-			++d.subco_index;
-		}
-	}
-		
-	for(i = 0; i < me->totvert; ++i) {
-		IndexNode *n;
-		multires_displacer_weight(&d, 1.0f / BLI_countlist(&map[i]));
-		for(n = map[i].first; n; n = n->next) {
-			multires_displacer_init(&d, dm, n->index, invert);
-			multires_displacer_anchor_vert(&d, i);
-			multires_displace(&d, mvert->co);
 		}
-		++mvert;
-		++d.subco_index;
 	}
 
-	if(!invert)
-		CDDM_calc_normals(dm);
+	if(!invert) {
+		ccgSubSurf_stitchFaces(ccgdm->ss, 0, NULL, 0);
+		ccgSubSurf_updateNormals(ccgdm->ss, NULL, 0);
+	}
 }
 
 static void multiresModifier_update(DerivedMesh *dm)
 {
+	CCGDerivedMesh *ccgdm= (CCGDerivedMesh*)dm;
 	Object *ob;
 	Mesh *me;
 	MDisps *mdisps;
+	MultiresModifierData *mmd;
 
-	ob = MultiresDM_get_object(dm);
-	me = MultiresDM_get_mesh(dm);
+	ob = ccgdm->multires.ob;
+	me = ccgdm->multires.ob->data;
+	mmd = ccgdm->multires.mmd;
+	// XXX CustomData_external_read(&me->fdata, CD_MASK_MDISPS, me->totface);
 	mdisps = CustomData_get_layer(&me->fdata, CD_MDISPS);
 
 	if(mdisps) {
-		const int lvl = MultiresDM_get_lvl(dm);
-		const int totlvl = MultiresDM_get_totlvl(dm);
+		int lvl = ccgdm->multires.lvl;
+		int totlvl = ccgdm->multires.totlvl;
 		
 		if(lvl < totlvl) {
-			/* Propagate disps upwards */
-			DerivedMesh *final, *subco_dm, *orig;
-			MVert *verts_new = NULL, *cur_lvl_orig_verts = NULL;
-			MultiresModifierData mmd;
-			int i;
-
-			orig = CDDM_from_mesh(me, NULL);
-			
-			/* Regenerate the current level's vertex coordinates
-			   (includes older displacements but not new sculpts) */
-			mmd.totlvl = totlvl;
-			mmd.lvl = lvl;
-			subco_dm = multires_dm_create_from_derived(&mmd, 1, orig, ob, 0, 0);
-			cur_lvl_orig_verts = CDDM_get_verts(subco_dm);
-
-			/* Subtract the original vertex cos from the new vertex cos */
-			verts_new = CDDM_get_verts(dm);
-			for(i = 0; i < dm->getNumVerts(dm); ++i)
-				sub_v3_v3v3(verts_new[i].co, verts_new[i].co, cur_lvl_orig_verts[i].co);
-
-			final = multires_subdisp_pre(dm, totlvl - lvl, 0);
-
-			multires_subdisp(orig, ob, final, lvl, totlvl, dm->getNumVerts(dm), dm->getNumEdges(dm),
-					 dm->getNumFaces(dm), 1);
-
-			subco_dm->release(subco_dm);
-			orig->release(orig);
+			Mesh *me = ob->data;
+			DerivedMesh *lowdm, *cddm, *highdm;
+			DMGridData **highGridData, **lowGridData, **subGridData, **gridData, *diffGrid;
+			CCGSubSurf *ss;
+			int i, j, numGrids, highGridSize, lowGridSize;
+
+			/* create subsurf DM from original mesh at high level */
+			cddm = CDDM_from_mesh(me, NULL);
+			highdm = subsurf_dm_create_local(ob, cddm, totlvl, mmd->simple);
+
+			/* create multires DM from original mesh and displacements */
+			lowdm = multires_dm_create_local(ob, cddm, lvl, totlvl, mmd->simple);
+			cddm->release(cddm);
+
+			/* gather grid data */
+			numGrids = highdm->getNumGrids(highdm);
+			highGridSize = highdm->getGridSize(highdm);
+			highGridData = highdm->getGridData(highdm);
+			lowGridSize = lowdm->getGridSize(lowdm);
+			lowGridData = lowdm->getGridData(lowdm);
+			gridData = dm->getGridData(dm);
+
+			subGridData = MEM_callocN(sizeof(DMGridData*)*numGrids, "subGridData*");
+			diffGrid = MEM_callocN(sizeof(DMGridData)*lowGridSize*lowGridSize, "diff");
+
+			for(i = 0; i < numGrids; ++i) {
+				/* backup subsurf grids */
+				subGridData[i] = MEM_callocN(sizeof(DMGridData)*highGridSize*highGridSize, "subGridData");
+				memcpy(subGridData[i], highGridData[i], sizeof(DMGridData)*highGridSize*highGridSize);
+
+				/* write difference of subsurf and displaced low level into high subsurf */
+				for(j = 0; j < lowGridSize*lowGridSize; ++j)
+					sub_v3_v3v3(diffGrid[j].co, gridData[i][j].co, lowGridData[i][j].co);
+
+				multires_copy_dm_grid(highGridData[i], diffGrid, highGridSize, lowGridSize);
+			}
+
+			/* lower level dm no longer needed at this point */
+			MEM_freeN(diffGrid);
+			lowdm->release(lowdm);
+
+			/* subsurf higher levels again with difference of coordinates */
+			ss= ((CCGDerivedMesh*)highdm)->ss;
+			ccgSubSurf_updateFromFaces(ss, lvl, NULL, 0);
+			ccgSubSurf_updateLevels(ss, lvl, NULL, 0);
+
+			/* add to displacements */
+			multiresModifier_disp_run(highdm, me, 1, 1, subGridData, mmd->totlvl);
+
+			/* free */
+			highdm->release(highdm);
+			for(i = 0; i < numGrids; ++i)
+				MEM_freeN(subGridData[i]);
+			MEM_freeN(subGridData);
+		}
+		else {
+			DerivedMesh *cddm, *subdm;
+
+			cddm = CDDM_from_mesh(me, NULL);
+			subdm = subsurf_dm_create_local(ob, cddm, mmd->totlvl, mmd->simple);
+			cddm->release(cddm);
+
+			multiresModifier_disp_run(dm, me, 1, 0, subdm->getGridData(subdm), mmd->totlvl);
+
+			subdm->release(subdm);
 		}
-		else
-			multiresModifier_disp_run(dm, MultiresDM_get_subco(dm), 1);
 	}
 }
 
 void multires_mark_as_modified(struct Object *ob)
 {
 	if(ob && ob->derivedFinal) {
-		MultiresDM_mark_as_modified(ob->derivedFinal);
+		CCGDerivedMesh *ccgdm = (CCGDerivedMesh*)ob->derivedFinal;
+		ccgdm->multires.modified = 1;
 	}
 }
 
@@ -1234,24 +692,47 @@ void multires_force_update(Object *ob)
 struct DerivedMesh *multires_dm_create_from_derived(MultiresModifierData *mmd, int local_mmd, DerivedMesh *dm, Object *ob,
 						    int useRenderParams, int isFinalCalc)
 {
-	SubsurfModifierData smd;
-	MultiresSubsurf ms;
+	//Mesh *me= ob->data;
 	DerivedMesh *result;
-	int i;
+	CCGDerivedMesh *ccgdm;
+	DMGridData **gridData, **subGridData;
+	int lvl= multires_get_level(ob, mmd, useRenderParams);
+	int i, gridSize, numGrids;
+
+	if(lvl == 0)
+		return dm;
+
+	result = subsurf_dm_create_local(ob, dm, lvl, 0);
+
+	if(!local_mmd) {
+		ccgdm = (CCGDerivedMesh*)result;
+
+		ccgdm->multires.ob = ob;
+		ccgdm->multires.mmd = mmd;
+		ccgdm->multires.local_mmd = local_mmd;
+		ccgdm->multires.lvl = lvl;
+		ccgdm->multires.totlvl = mmd->totlvl;
+		ccgdm->multires.modified = 0;
+		ccgdm->multires.update = multiresModifier_update;
+	}
 
-	ms.mmd = mmd;
-	ms.ob = ob;
-	ms.local_mmd = local_mmd;
+	numGrids = result->getNumGrids(result);
+	gridSize = result->getGridSize(result);
+	gridData = result->getGridData(result);
 
-	memset(&smd, 0, sizeof(SubsurfModifierData));
-	smd.levels = smd.renderLevels = mmd->lvl - 1;
-	smd.flags |= eSubsurfModifierFlag_SubsurfUv;
+	subGridData = MEM_callocN(sizeof(DMGridData*)*numGrids, "subGridData*");
 
-	result = NULL; // XXX subsurf_make_derived_from_derived_with_multires(dm, &smd, &ms, useRenderParams, NULL, isFinalCalc, 0);
-	for(i = 0; i < result->getNumVerts(result); ++i)
-		MultiresDM_get_subco(result)[i] = CDDM_get_verts(result)[i];
-	multiresModifier_disp_run(result, MultiresDM_get_subco(result), 0);
-	MultiresDM_set_update(result, multiresModifier_update);
+	for(i = 0; i < numGrids; i++) {
+		subGridData[i] = MEM_callocN(sizeof(DMGridData)*gridSize*gridSize, "subGridData");
+		memcpy(subGridData[i], gridData[i], sizeof(DMGridData)*gridSize*gridSize);
+	}
+
+	// XXX CustomData_external_read(&me->fdata, CD_MASK_MDISPS, me->totface);
+	multiresModifier_disp_run(result, ob->data, 0, 0, subGridData, mmd->totlvl);
+
+	for(i = 0; i < numGrids; i++)
+		MEM_freeN(subGridData[i]);
+	MEM_freeN(subGridData);
 
 	return result;
 }
@@ -1425,9 +906,9 @@ void multires_load_old(DerivedMesh *dm, Multires *mr)
 	MultiresLevel *lvl, *lvl1;
 	MVert *vsrc, *vdst;
 	int src, dst;
-	int totlvl = MultiresDM_get_totlvl(dm);
-	int st = multires_side_tot[totlvl - 2] - 1;
-	int extedgelen = multires_side_tot[totlvl - 1] - 2;
+	int totlvl = 2; // XXX MultiresDM_get_totlvl(dm);
+	int st = multires_side_tot[totlvl - 1] - 1;
+	int extedgelen = multires_side_tot[totlvl] - 2;
 	int *vvmap; // inorder for dst, map to src
 	int crossedgelen;
 	int i, j, s, x, totvert, tottri, totquad;
@@ -1454,9 +935,9 @@ void multires_load_old(DerivedMesh *dm, Multires *mr)
 		lvl = lvl1->next;
 
 		for(j = 2; j <= mr->level_count; ++j) {
-			int base = multires_side_tot[totlvl - j] - 2;
-			int skip = multires_side_tot[totlvl - j + 1] - 1;
-			int st = multires_side_tot[j - 2] - 1;
+			int base = multires_side_tot[totlvl - j + 1] - 2;
+			int skip = multires_side_tot[totlvl - j + 2] - 1;
+			int st = multires_side_tot[j - 1] - 1;
 
 			for(x = 0; x < st; ++x)
 				vvmap[ldst + base + x * skip] = lsrc + st * i + x;
@@ -1483,7 +964,7 @@ void multires_load_old(DerivedMesh *dm, Multires *mr)
 
 		/* Face edge cross */
 		tottri = totquad = 0;
-		crossedgelen = multires_side_tot[totlvl - 2] - 2;
+		crossedgelen = multires_side_tot[totlvl - 1] - 2;
 		dst = 0;
 		for(i = 0; i < lvl1->totface; ++i) {
 			int sides = lvl1->faces[i].v[3] ? 4 : 3;
@@ -1492,8 +973,8 @@ void multires_load_old(DerivedMesh *dm, Multires *mr)
 			++dst;
 
 			for(j = 3; j <= mr->level_count; ++j) {
-				int base = multires_side_tot[totlvl - j] - 2;
-				int skip = multires_side_tot[totlvl - j + 1] - 1;
+				int base = multires_side_tot[totlvl - j + 1] - 2;
+				int skip = multires_side_tot[totlvl - j + 2] - 1;
 				int st = pow(2, j - 2);
 				int st2 = pow(2, j - 3);
 				int lsrc = lvl->prev->totvert;
@@ -1541,8 +1022,8 @@ void multires_load_old(DerivedMesh *dm, Multires *mr)
 			int ldst = dst + 1 + sides * (st - 1);
 
 			for(s = 0; s < sides; ++s) {
-				int st2 = multires_side_tot[totlvl - 2] - 2;
-				int st3 = multires_side_tot[totlvl - 3] - 2;
+				int st2 = multires_side_tot[totlvl - 1] - 2;
+				int st3 = multires_side_tot[totlvl - 2] - 2;
 				int st4 = st3 == 0 ? 1 : (st3 + 1) / 2;
 				int mid = ldst + st2 * st3 + st3;
 				int cv = lvl1->faces[j].v[s];
@@ -1583,3 +1064,4 @@ void multires_load_old(DerivedMesh *dm, Multires *mr)
 
 	MEM_freeN(vvmap);
 }
+
diff --git a/source/blender/blenloader/intern/readfile.c b/source/blender/blenloader/intern/readfile.c
index 1fa9090ba45..a9ceb77ad9f 100644
--- a/source/blender/blenloader/intern/readfile.c
+++ b/source/blender/blenloader/intern/readfile.c
@@ -3922,12 +3922,6 @@ static void direct_link_modifiers(FileData *fd, ListBase *lb)
 						SWITCH_INT(mmd->dynverts[a])
 			}
 		}
-		else if (md->type==eModifierType_Multires) {
-			MultiresModifierData *mmd = (MultiresModifierData*) md;
-			
-			mmd->undo_verts = newdataadr(fd, mmd->undo_verts);
-			mmd->undo_signal = !!mmd->undo_verts;
-		}
 	}
 }
 
@@ -9595,7 +9589,7 @@ static void do_versions(FileData *fd, Library *lib, Main *main)
 		ToolSettings *ts;
 		//PTCacheID *pid;
 		//ListBase pidlist;
-		int i, a;
+		int /*i, */a;
 
 		for(ob = main->object.first; ob; ob = ob->id.next) {
 			//BKE_ptcache_ids_from_object(&pidlist, ob);
@@ -9613,6 +9607,8 @@ static void do_versions(FileData *fd, Library *lib, Main *main)
 				ob->data = me;
 
 				if(me && me->id.lib==NULL && me->mr) { /* XXX - library meshes crash on loading most yoFrankie levels, the multires pointer gets invalid -  Campbell */
+					// XXX
+#if 0
 					MultiresLevel *lvl;
 					ModifierData *md;
 					MultiresModifierData *mmd;
@@ -9648,7 +9644,8 @@ static void do_versions(FileData *fd, Library *lib, Main *main)
 					mmd = (MultiresModifierData*)modifier_new(eModifierType_Multires);
 					BLI_insertlinkbefore(&ob->modifiers, md, mmd);
 
-					multiresModifier_subdivide(mmd, ob, me->mr->level_count - 1, 1, 0);
+					for(i = 0; i < me->mr->level_count - 1; ++i)
+						multiresModifier_subdivide(mmd, ob, 1, 0);
 
 					mmd->lvl = mmd->totlvl;
 					orig = CDDM_from_mesh(me, NULL);
@@ -9662,6 +9659,7 @@ static void do_versions(FileData *fd, Library *lib, Main *main)
 
 					/* Remove the old multires */
 					multires_free(me->mr);
+#endif
 					me->mr = NULL;
 				}
 
diff --git a/source/blender/blenloader/intern/writefile.c b/source/blender/blenloader/intern/writefile.c
index b2147221f9f..b00cd10c6a7 100644
--- a/source/blender/blenloader/intern/writefile.c
+++ b/source/blender/blenloader/intern/writefile.c
@@ -1214,12 +1214,6 @@ static void write_modifiers(WriteData *wd, ListBase *modbase)
 			writestruct(wd, DATA, "MDefInfluence", mmd->totinfluence, mmd->dyninfluences);
 			writedata(wd, DATA, sizeof(int)*mmd->totvert, mmd->dynverts);
 		}
-		else if (md->type==eModifierType_Multires) {
-			MultiresModifierData *mmd = (MultiresModifierData*) md;
-
-			if(mmd->undo_verts)
-				writestruct(wd, DATA, "MVert", mmd->undo_verts_tot, mmd->undo_verts);
-		}
 	}
 }
 
diff --git a/source/blender/editors/object/object_modifier.c b/source/blender/editors/object/object_modifier.c
index c4304056017..9da7fa94295 100644
--- a/source/blender/editors/object/object_modifier.c
+++ b/source/blender/editors/object/object_modifier.c
@@ -373,7 +373,7 @@ int ED_object_modifier_apply(ReportList *reports, Scene *scene, Object *ob, Modi
 
 		BKE_report(reports, RPT_INFO, "Applied modifier only changed CV points, not tesselated/bevel vertices");
 
-		if (!(md->mode&eModifierMode_Realtime) || (mti->isDisabled && mti->isDisabled(md))) {
+		if (!(md->mode&eModifierMode_Realtime) || (mti->isDisabled && mti->isDisabled(md, 0))) {
 			BKE_report(reports, RPT_ERROR, "Modifier is disabled, skipping apply");
 			return 0;
 		}
@@ -684,6 +684,13 @@ void OBJECT_OT_modifier_copy(wmOperatorType *ot)
 
 /************* multires delete higher levels operator ****************/
 
+static int multires_poll(bContext *C)
+{
+	PointerRNA ptr= CTX_data_pointer_get_type(C, "modifier", &RNA_MultiresModifier);
+	ID *id= ptr.id.data;
+	return (ptr.data && id && !id->lib);
+}
+
 static int multires_higher_levels_delete_exec(bContext *C, wmOperator *op)
 {
 	PointerRNA ptr= CTX_data_pointer_get_type(C, "modifier", &RNA_MultiresModifier);
@@ -702,8 +709,8 @@ void OBJECT_OT_multires_higher_levels_delete(wmOperatorType *ot)
 {
 	ot->name= "Delete Higher Levels";
 	ot->idname= "OBJECT_OT_multires_higher_levels_delete";
-	ot->poll= ED_operator_object_active;
 
+	ot->poll= multires_poll;
 	ot->exec= multires_higher_levels_delete_exec;
 	
 	/* flags */
@@ -718,7 +725,7 @@ static int multires_subdivide_exec(bContext *C, wmOperator *op)
 	Object *ob= ptr.id.data;
 	MultiresModifierData *mmd= ptr.data;
 
-	multiresModifier_subdivide(mmd, ob, 1, 0, mmd->simple);
+	multiresModifier_subdivide(mmd, ob, 0, mmd->simple);
 
 	DAG_id_flush_update(&ob->id, OB_RECALC_DATA);
 	WM_event_add_notifier(C, NC_OBJECT|ND_MODIFIER, ob);
diff --git a/source/blender/editors/sculpt_paint/sculpt.c b/source/blender/editors/sculpt_paint/sculpt.c
index c9e351458ad..82893b48af0 100644
--- a/source/blender/editors/sculpt_paint/sculpt.c
+++ b/source/blender/editors/sculpt_paint/sculpt.c
@@ -2027,13 +2027,13 @@ static int sculpt_toggle_mode(bContext *C, wmOperator *op)
 {
 	ToolSettings *ts = CTX_data_tool_settings(C);
 	Object *ob = CTX_data_active_object(C);
-	//MultiresModifierData *mmd = sculpt_multires_active(ob);
+	MultiresModifierData *mmd = sculpt_multires_active(ob);
 
 	if(ob->mode & OB_MODE_SCULPT) {
 		multires_force_update(ob);
 
-		/*if(mmd && mmd->sculptlvl != mmd->lvl)
-			DAG_id_flush_update(&ob->id, OB_RECALC_DATA);*/
+		if(mmd && mmd->sculptlvl != mmd->lvl)
+			DAG_id_flush_update(&ob->id, OB_RECALC_DATA);
 
 		/* Leave sculptmode */
 		ob->mode &= ~OB_MODE_SCULPT;
@@ -2044,8 +2044,8 @@ static int sculpt_toggle_mode(bContext *C, wmOperator *op)
 		/* Enter sculptmode */
 		ob->mode |= OB_MODE_SCULPT;
 
-		/*if(mmd && mmd->sculptlvl != mmd->lvl)
-			DAG_id_flush_update(&ob->id, OB_RECALC_DATA);*/
+		if(mmd && mmd->sculptlvl != mmd->lvl)
+			DAG_id_flush_update(&ob->id, OB_RECALC_DATA);
 		
 		/* Create persistent sculpt mode data */
 		if(!ts->sculpt)
diff --git a/source/blender/makesdna/DNA_modifier_types.h b/source/blender/makesdna/DNA_modifier_types.h
index fe6a5b050e3..d6e7992d435 100644
--- a/source/blender/makesdna/DNA_modifier_types.h
+++ b/source/blender/makesdna/DNA_modifier_types.h
@@ -581,12 +581,8 @@ typedef struct ExplodeModifierData {
 typedef struct MultiresModifierData {
 	ModifierData modifier;
 
-	struct MVert *undo_verts; /* Store DerivedMesh vertices for multires undo */
-	int undo_verts_tot; /* Length of undo_verts array */
-	char undo_signal; /* If true, signals to replace verts with undo verts */
-
-	char lvl, totlvl;
-	char simple;
+	char lvl, sculptlvl, renderlvl, totlvl;
+	char simple, pad[3];
 } MultiresModifierData;
 
 typedef struct FluidsimModifierData {
diff --git a/source/blender/makesrna/intern/rna_modifier.c b/source/blender/makesrna/intern/rna_modifier.c
index 93972894ef1..689599c5cdf 100644
--- a/source/blender/makesrna/intern/rna_modifier.c
+++ b/source/blender/makesrna/intern/rna_modifier.c
@@ -39,6 +39,7 @@
 
 #include "BKE_animsys.h"
 #include "BKE_bmesh.h" /* For BevelModifierData */
+#include "BKE_global.h"
 #include "BKE_smoke.h" /* For smokeModifier_free & smokeModifier_createType */
 
 #include "WM_api.h"
@@ -335,10 +336,36 @@ static void rna_MultiresModifier_level_range(PointerRNA *ptr, int *min, int *max
 {
 	MultiresModifierData *mmd = (MultiresModifierData*)ptr->data;
 
-	*min = 1;
+	*min = 0;
 	*max = mmd->totlvl;
 }
 
+/*static int rna_MultiresModifier_external_get(PointerRNA *ptr)
+{
+	Object *ob= (Object*)ptr->id.data;
+	Mesh *me= ob->data;
+
+	return CustomData_external_test(&me->fdata, CD_MDISPS);
+}
+
+static void rna_MultiresModifier_external_set(PointerRNA *ptr, int value)
+{
+	Object *ob= (Object*)ptr->id.data;
+	Mesh *me= ob->data;
+
+	if(CustomData_external_test(&me->fdata, CD_MDISPS) && !value)
+		CustomData_external_remove(&me->fdata, CD_MDISPS, me->totface);
+	else if(!CustomData_external_test(&me->fdata, CD_MDISPS) && value)
+		CustomData_external_add(&me->fdata, CD_MDISPS, me->id.name+2, me->totface);
+}
+
+static int rna_MultiresModifier_external_editable(PointerRNA *ptr)
+{
+	MultiresModifierData *mmd = ptr->data;
+
+	return (G.save_over && mmd->totlvl > 0);
+}*/
+
 static void modifier_object_set(Object *self, Object **ob_p, int type, PointerRNA value)
 {
 	Object *ob= value.data;
@@ -487,17 +514,15 @@ static void rna_def_modifier_subsurf(BlenderRNA *brna)
 
 	rna_def_property_subdivision_common(srna, "subdivType");
 
-	prop= RNA_def_property(srna, "levels", PROP_INT, PROP_NONE);
+	prop= RNA_def_property(srna, "levels", PROP_INT, PROP_UNSIGNED);
 	RNA_def_property_int_sdna(prop, NULL, "levels");
-	RNA_def_property_range(prop, 1, 6);
-	RNA_def_property_ui_range(prop, 1, 6, 1, 0);
+	RNA_def_property_ui_range(prop, 0, 6, 1, 0);
 	RNA_def_property_ui_text(prop, "Levels", "Number of subdivisions to perform.");
 	RNA_def_property_update(prop, 0, "rna_Modifier_update");
 
-	prop= RNA_def_property(srna, "render_levels", PROP_INT, PROP_NONE);
+	prop= RNA_def_property(srna, "render_levels", PROP_INT, PROP_UNSIGNED);
 	RNA_def_property_int_sdna(prop, NULL, "renderLevels");
-	RNA_def_property_range(prop, 1, 6);
-	RNA_def_property_ui_range(prop, 1, 6, 1, 0);
+	RNA_def_property_ui_range(prop, 0, 6, 1, 0);
 	RNA_def_property_ui_text(prop, "Render Levels", "Number of subdivisions to perform when rendering.");
 
 	prop= RNA_def_property(srna, "optimal_draw", PROP_BOOLEAN, PROP_NONE);
@@ -523,11 +548,32 @@ static void rna_def_modifier_multires(BlenderRNA *brna)
 
 	rna_def_property_subdivision_common(srna, "simple");
 
-	prop= RNA_def_property(srna, "level", PROP_INT, PROP_NONE);
+	prop= RNA_def_property(srna, "levels", PROP_INT, PROP_UNSIGNED);
 	RNA_def_property_int_sdna(prop, NULL, "lvl");
-	RNA_def_property_ui_text(prop, "Level", "");
+	RNA_def_property_ui_text(prop, "Levels", "Number of subdivisions to use in the viewport.");
+	RNA_def_property_int_funcs(prop, NULL, NULL, "rna_MultiresModifier_level_range");
+	RNA_def_property_update(prop, 0, "rna_Modifier_update");
+
+	prop= RNA_def_property(srna, "sculpt_levels", PROP_INT, PROP_UNSIGNED);
+	RNA_def_property_int_sdna(prop, NULL, "sculptlvl");
+	RNA_def_property_ui_text(prop, "Sculpt Levels", "Number of subdivisions to use in sculpt mode.");
 	RNA_def_property_int_funcs(prop, NULL, NULL, "rna_MultiresModifier_level_range");
 	RNA_def_property_update(prop, 0, "rna_Modifier_update");
+
+	prop= RNA_def_property(srna, "render_levels", PROP_INT, PROP_UNSIGNED);
+	RNA_def_property_int_sdna(prop, NULL, "renderlvl");
+	RNA_def_property_ui_text(prop, "Render Levels", "");
+	RNA_def_property_int_funcs(prop, NULL, NULL, "rna_MultiresModifier_level_range");
+
+	prop= RNA_def_property(srna, "total_levels", PROP_INT, PROP_UNSIGNED);
+	RNA_def_property_int_sdna(prop, NULL, "totlvl");
+	RNA_def_property_clear_flag(prop, PROP_EDITABLE);
+	RNA_def_property_ui_text(prop, "Total Levels", "Number of subdivisions for which displacements are stored.");
+
+	/*prop= RNA_def_property(srna, "external", PROP_BOOLEAN, PROP_NONE);
+	RNA_def_property_boolean_funcs(prop, "rna_MultiresModifier_external_get", "rna_MultiresModifier_external_set");
+	RNA_def_property_editable_func(prop, "rna_MultiresModifier_external_editable");
+	RNA_def_property_ui_text(prop, "External", "Store multires displacements outside the .blend file, to save memory.");*/
 }
 
 static void rna_def_modifier_lattice(BlenderRNA *brna)