diff --git a/source/blender/editors/space_node/drawnode.c b/source/blender/editors/space_node/drawnode.c
index 970eccb8be3..219aa3261c7 100644
--- a/source/blender/editors/space_node/drawnode.c
+++ b/source/blender/editors/space_node/drawnode.c
@@ -1538,6 +1538,7 @@ static void node_composit_buts_map_uv(uiLayout *layout, bContext *UNUSED(C), Poi
 static void node_composit_buts_id_mask(uiLayout *layout, bContext *UNUSED(C), PointerRNA *ptr)
 {
 	uiItemR(layout, ptr, "index", 0, NULL, ICON_NONE);
+	uiItemR(layout, ptr, "smooth_mask", 0, NULL, ICON_NONE);
 }
 
 static void node_composit_buts_file_output(uiLayout *layout, bContext *UNUSED(C), PointerRNA *ptr)
diff --git a/source/blender/makesrna/intern/rna_nodetree.c b/source/blender/makesrna/intern/rna_nodetree.c
index 1b113620663..23a71b20c32 100644
--- a/source/blender/makesrna/intern/rna_nodetree.c
+++ b/source/blender/makesrna/intern/rna_nodetree.c
@@ -1874,6 +1874,11 @@ static void def_cmp_id_mask(StructRNA *srna)
 	RNA_def_property_range(prop, 0, 10000);
 	RNA_def_property_ui_text(prop, "Index", "Pass index number to convert to alpha");
 	RNA_def_property_update(prop, NC_NODE|NA_EDITED, "rna_Node_update");
+
+	prop = RNA_def_property(srna, "smooth_mask", PROP_BOOLEAN, PROP_NONE);
+	RNA_def_property_boolean_sdna(prop, NULL, "custom2", 0);
+	RNA_def_property_ui_text(prop, "Smooth Mask", "Apply an anti-aliasing filter to the mask");
+	RNA_def_property_update(prop, NC_NODE|NA_EDITED, "rna_Node_update");
 }
 
 static void def_cmp_map_uv(StructRNA *srna)
diff --git a/source/blender/nodes/composite/nodes/node_composite_idMask.c b/source/blender/nodes/composite/nodes/node_composite_idMask.c
index 43f78a90add..ddab415b3be 100644
--- a/source/blender/nodes/composite/nodes/node_composite_idMask.c
+++ b/source/blender/nodes/composite/nodes/node_composite_idMask.c
@@ -99,7 +99,7 @@ static void node_composit_exec_idmask(void *data, bNode *node, bNodeStack **in,
 		
 		stackbuf= alloc_compbuf(cbuf->x, cbuf->y, CB_VAL, 1); /* allocs */;
 		
-		if(rd->scemode & R_FULL_SAMPLE)
+		if((rd->scemode & R_FULL_SAMPLE) || node->custom2 == 0)
 			do_idmask_fsa(stackbuf, cbuf, (float)node->custom1);
 		else
 			do_idmask(stackbuf, cbuf, (float)node->custom1);