Index: source/blender/editors/metaball/mball_ops.c
===================================================================
--- source/blender/editors/metaball/mball_ops.c	(révision 45380)
+++ source/blender/editors/metaball/mball_ops.c	(copie de travail)
@@ -51,6 +51,7 @@
        WM_operatortype_append(MBALL_OT_reveal_metaelems);

        WM_operatortype_append(MBALL_OT_select_all);
+	WM_operatortype_append(MBALL_OT_select_similar);
        WM_operatortype_append(MBALL_OT_select_random_metaelems);
 }

@@ -79,6 +80,8 @@
        kmi = WM_keymap_add_item(keymap, "MBALL_OT_select_all", IKEY, KM_PRESS, KM_CTRL, 0);
                RNA_enum_set(kmi->ptr, "action", SEL_INVERT);

+	kmi = WM_keymap_add_item(keymap, "MBALL_OT_select_similar", GKEY, KM_PRESS, KM_SHIFT, 0);
+
        ED_object_generic_keymap(keyconf, keymap, 3);
 }

Index: source/blender/editors/metaball/mball_intern.h
===================================================================
--- source/blender/editors/metaball/mball_intern.h	(révision 45380)
+++ source/blender/editors/metaball/mball_intern.h	(copie de travail)
@@ -43,6 +43,7 @@
 void MBALL_OT_duplicate_metaelems(struct wmOperatorType *ot);

 void MBALL_OT_select_all(struct wmOperatorType *ot);
+void MBALL_OT_select_similar(struct wmOperatorType *ot);
 void MBALL_OT_select_random_metaelems(struct wmOperatorType *ot);

 #endif
Index: source/blender/editors/metaball/mball_edit.c
===================================================================
--- source/blender/editors/metaball/mball_edit.c	(révision 45380)
+++ source/blender/editors/metaball/mball_edit.c	(copie de travail)
@@ -181,6 +181,146 @@
        WM_operator_properties_select_all(ot);
 }

+/* ****************** SIMILAR "group" SELECTS. ****************** */
+
+enum {
+	SIMMBALL_RADIUS = 1,
+	SIMMBALL_TYPE,
+	SIMMBALL_ROTATION
+};
+
+static EnumPropertyItem prop_similar_types[] = {
+    {SIMMBALL_RADIUS, "RADIUS", 0, "Radius", ""},
+    {SIMMBALL_TYPE, "TYPE", 0, "Type", ""},
+    {SIMMBALL_ROTATION, "ROTATION", 0, "Rotation", ""},
+
+    {0, NULL, 0, NULL, NULL}
+};
+
+static void select_similar_radius(MetaBall *mb, float thresh)
+{
+	MetaElem *ml;
+	MetaElem *mlp;
+
+	ml = mb->editelems->first;
+	while (ml) {
+		if (ml->flag & SELECT) {
+			mlp = mb->editelems->first;
+
+			while (mlp) {
+				if (fabs(mlp->rad-ml->rad) <= thresh*ml->rad && mlp!=ml)
+					mlp->flag |=SELECT;
+				mlp = mlp->next;
+			}
+		}
+		ml= ml->next;
+	}
+}
+
+static void select_similar_type(MetaBall *mb)
+{
+	MetaElem *ml;
+	MetaElem *mlp;
+
+	ml = mb->editelems->first;
+	while (ml) {
+		if (ml->flag & SELECT) {
+			mlp = mb->editelems->first;
+			while (mlp) {
+				if (mlp->type == ml->type)
+					mlp->flag |=SELECT;
+				mlp = mlp->next;
+			}
+		}
+		ml= ml->next;
+	}
+}
+
+static void select_similar_rotation(MetaBall *mb)
+{
+	MetaElem *ml;
+	MetaElem *mlp;
+
+	ml = mb->editelems->first;
+	while (ml) {
+		if (ml->flag & SELECT) {
+			mlp = mb->editelems->first;
+			while (mlp) {
+				if (mlp->quat[0] == ml->quat[0] && mlp->quat[1] == ml->quat[1]
+					&& mlp->quat[2] == ml->quat[2] && mlp->quat[3] == ml->quat[3])
+					mlp->flag |=SELECT;
+				mlp = mlp->next;
+			}
+		}
+		ml= ml->next;
+	}
+}
+
+static int mball_select_similar_exec(bContext *C, wmOperator *op)
+{
+	Object *obedit= CTX_data_edit_object(C);
+	MetaBall *mb = (MetaBall*)obedit->data;
+
+	/*get the type from RNA */
+	int type = RNA_enum_get(op->ptr, "type");
+	float thresh = RNA_float_get(op->ptr, "threshold");
+
+	if (type == SIMMBALL_RADIUS) {
+		select_similar_radius(mb, thresh);
+	}
+	else if (type == SIMMBALL_TYPE) {
+		select_similar_type(mb);
+	}
+	else {
+		select_similar_rotation(mb);
+	}
+	WM_event_add_notifier(C, NC_GEOM|ND_SELECT, mb);
+
+	return OPERATOR_FINISHED;
+}
+
+static EnumPropertyItem *select_similar_type_itemf(bContext *C, PointerRNA *UNUSED(ptr), PropertyRNA *UNUSED(prop),
+                                                   int *free)
+{
+	Object *obedit = CTX_data_edit_object(C);
+
+	if (obedit && obedit->type == OB_MBALL) {
+		EnumPropertyItem *item = NULL;
+		int a, totitem = 0;
+		for (a = SIMMBALL_RADIUS; a <= SIMMBALL_ROTATION; a++) {
+			RNA_enum_items_add_value(&item, &totitem, prop_similar_types, a);
+		}
+		RNA_enum_item_end(&item, &totitem);
+		*free = 1;
+		return item;
+	}
+	return NULL;
+}
+
+void MBALL_OT_select_similar(wmOperatorType *ot)
+{
+	PropertyRNA *prop;
+
+	/* identifiers */
+	ot->name = "Select Similar";
+	ot->idname = "MBALL_OT_select_similar";
+
+	/* callback functions */
+	ot->invoke = WM_menu_invoke;
+	ot->exec = mball_select_similar_exec;
+	ot->poll = ED_operator_editmball;
+	ot->description = "Select similar metaballs by property types";
+
+	/* flags */
+	ot->flag = OPTYPE_REGISTER|OPTYPE_UNDO;
+
+	/* properties */
+	prop = ot->prop = RNA_def_enum(ot->srna, "type", prop_similar_types, 0, "Type", "");
+	RNA_def_enum_funcs(prop, select_similar_type_itemf);
+
+	RNA_def_float(ot->srna, "threshold", 0.0, 0.0, 1.0, "Threshold", "", 0.01, 1.0);
+}
+
 /***************************** Select random operator *****************************/

 /* Random metaball selection */