Index: release/scripts/startup/bl_ui/properties_particle.py
===================================================================
--- release/scripts/startup/bl_ui/properties_particle.py	(revision 56488)
+++ release/scripts/startup/bl_ui/properties_particle.py	(working copy)
@@ -249,6 +249,9 @@
             elif part.distribution == 'GRID':
                 row.prop(part, "grid_resolution")
                 row.prop(part, "grid_random", text="Random", slider=True)
+                
+        row = layout.row()
+        row.prop(part, "use_modified_mesh")
 
 
 class PARTICLE_PT_hair_dynamics(ParticleButtonsPanel, Panel):
Index: source/blender/blenkernel/intern/particle.c
===================================================================
--- source/blender/blenkernel/intern/particle.c	(revision 56488)
+++ source/blender/blenkernel/intern/particle.c	(working copy)
@@ -3640,6 +3640,8 @@
 
 	if (!part->effector_weights)
 		part->effector_weights = BKE_add_effector_weights(NULL);
+
+	part->use_modified_mesh = 0;
 }
 
 
Index: source/blender/blenkernel/intern/particle_system.c
===================================================================
--- source/blender/blenkernel/intern/particle_system.c	(revision 56488)
+++ source/blender/blenkernel/intern/particle_system.c	(working copy)
@@ -341,6 +341,8 @@
 	 *            each original elements can reference its derived elements
 	 */
 	Mesh *me= (Mesh*)ob->data;
+	/* modified dm support */
+	short use_modified_mesh = psys->part->use_modified_mesh;
 	PARTICLE_P;
 	
 	/* CACHE LOCATIONS */
@@ -351,17 +353,29 @@
 
 		if (psys->part->from == PART_FROM_VERT) {
 			totdmelem= dm->getNumVerts(dm);
-			totelem= me->totvert;
-			origindex= dm->getVertDataArray(dm, CD_ORIGINDEX);
+			if (use_modified_mesh) {
+				totelem = totdmelem;
+				origindex = NULL;
+			} else {
+				totelem= me->totvert;
+				origindex= dm->getVertDataArray(dm, CD_ORIGINDEX);
+			}
 		}
 		else { /* FROM_FACE/FROM_VOLUME */
 			totdmelem= dm->getNumTessFaces(dm);
-			totelem= me->totpoly;
-			origindex = dm->getTessFaceDataArray(dm, CD_ORIGINDEX);
-			/* for face lookups we need the poly origindex too */
-			origindex_poly = dm->getPolyDataArray(dm, CD_ORIGINDEX);
-			if (origindex_poly == NULL) {
-				origindex = NULL;
+
+			if (use_modified_mesh) {
+				totelem= totdmelem;
+				origindex= NULL;
+				origindex_poly= NULL;
+			} else {
+				totelem= me->totpoly;
+				origindex = dm->getTessFaceDataArray(dm, CD_ORIGINDEX);
+				/* for face lookups we need the poly origindex too */
+				origindex_poly = dm->getPolyDataArray(dm, CD_ORIGINDEX);
+				if (origindex_poly == NULL) {
+					origindex = NULL;
+				}
 			}
 		}
 	
@@ -373,11 +387,15 @@
 			node->link = SET_INT_IN_POINTER(i);
 
 			/* may be vertex or face origindex */
-			origindex_final = origindex ? origindex[i] : ORIGINDEX_NONE;
+			if (use_modified_mesh)
+				origindex_final = i;
+			else {
+				origindex_final = origindex ? origindex[i] : ORIGINDEX_NONE;
 
-			/* if we have a poly source, do an index lookup */
-			if (origindex_poly && origindex_final != ORIGINDEX_NONE) {
-				origindex_final = origindex_poly[origindex_final];
+				/* if we have a poly source, do an index lookup */
+				if (origindex_poly && origindex_final != ORIGINDEX_NONE) {
+					origindex_final = origindex_poly[origindex_final];
+				}
 			}
 
 			if (origindex_final != ORIGINDEX_NONE) {
@@ -406,7 +424,10 @@
 			else { /* FROM_FACE/FROM_VOLUME */
 				/* Note that sometimes the pa->num is over the nodearray size, this is bad, maybe there is a better place to fix this,
 				 * but for now passing NULL is OK. every face will be searched for the particle so its slower - Campbell */
-				pa->num_dmcache= psys_particle_dm_face_lookup(ob, dm, pa->num, pa->fuv, pa->num < totelem ? nodearray[pa->num] : NULL);
+				if (use_modified_mesh)
+					pa->num_dmcache = GET_INT_FROM_POINTER(nodearray[pa->num]->link);
+				else
+					pa->num_dmcache= psys_particle_dm_face_lookup(ob, dm, pa->num, pa->fuv, pa->num < totelem ? nodearray[pa->num] : NULL);
 			}
 		}
 
@@ -1110,7 +1131,10 @@
 		distr = part->distr;
 		BLI_rng_srandom(ctx->sim.rng, 31415926 + psys->seed);
 		
-		dm= CDDM_from_mesh((Mesh*)ob->data, ob);
+		if (psys->part->use_modified_mesh)
+			dm = finaldm;
+		else
+			dm= CDDM_from_mesh((Mesh*)ob->data, ob);
 
 		/* BMESH ONLY, for verts we don't care about tessfaces */
 		if (from != PART_FROM_VERT) {
@@ -1118,7 +1142,8 @@
 		}
 
 		/* we need orco for consistent distributions */
-		DM_add_vert_layer(dm, CD_ORCO, CD_ASSIGN, BKE_mesh_orco_verts_get(ob));
+		if (!CustomData_has_layer(&dm->vertData, CD_ORCO))
+			DM_add_vert_layer(dm, CD_ORCO, CD_ASSIGN, BKE_mesh_orco_verts_get(ob));
 
 		if (from == PART_FROM_VERT) {
 			MVert *mv= dm->getVertDataArray(dm, CD_MVERT);
Index: source/blender/makesdna/DNA_particle_types.h
===================================================================
--- source/blender/makesdna/DNA_particle_types.h	(revision 56488)
+++ source/blender/makesdna/DNA_particle_types.h	(working copy)
@@ -243,6 +243,11 @@
 	struct Ipo *ipo  DNA_DEPRECATED;  /* old animation system, deprecated for 2.5 */
 	struct PartDeflect *pd;
 	struct PartDeflect *pd2;
+
+	/* modified dm support */
+	short use_modified_mesh;
+	short pad[3];
+
 } ParticleSettings;
 
 typedef struct ParticleSystem {
Index: source/blender/makesrna/intern/rna_particle.c
===================================================================
--- source/blender/makesrna/intern/rna_particle.c	(revision 56488)
+++ source/blender/makesrna/intern/rna_particle.c	(working copy)
@@ -2933,6 +2933,12 @@
 	RNA_def_property_ui_text(prop, "Loop count", "Number of times the keys are looped");
 	RNA_def_property_update(prop, 0, "rna_Particle_redo");
 	
+	/* modified dm support */
+	prop = RNA_def_property(srna, "use_modified_mesh", PROP_BOOLEAN, PROP_NONE);
+	RNA_def_property_boolean_sdna(prop, NULL, "use_modified_mesh", 0);
+	RNA_def_property_ui_text(prop, "Use Modified", "Use modified mesh for emitting");
+	RNA_def_property_update(prop, 0, "rna_Particle_change_type");
+
 	/* draw objects & groups */
 	prop = RNA_def_property(srna, "dupli_group", PROP_POINTER, PROP_NONE);
 	RNA_def_property_pointer_sdna(prop, NULL, "dup_group");