diff --git a/modular_ss220/aesthetics/walls/code/walls.dm b/modular_ss220/aesthetics/walls/code/walls.dm
index 91c8105b1c74..5c9f97a1aa46 100644
--- a/modular_ss220/aesthetics/walls/code/walls.dm
+++ b/modular_ss220/aesthetics/walls/code/walls.dm
@@ -1,14 +1,29 @@
 /turf/simulated/wall
 	icon = 'modular_ss220/aesthetics/walls/icons/wall.dmi'
+	smoothing_groups = list(SMOOTH_GROUP_SIMULATED_TURFS, SMOOTH_GROUP_WALLS, SMOOTH_GROUP_REGULAR_WALLS)
+	canSmoothWith = list(SMOOTH_GROUP_WALLS, SMOOTH_GROUP_REGULAR_WALLS, SMOOTH_GROUP_REINFORCED_WALLS, SMOOTH_GROUP_AIRLOCK, SMOOTH_GROUP_WINDOW_FULLTILE)
 
 /turf/simulated/wall/r_wall
 	icon = 'modular_ss220/aesthetics/walls/icons/reinforced_wall.dmi'
+	canSmoothWith = list(SMOOTH_GROUP_WALLS, SMOOTH_GROUP_REGULAR_WALLS, SMOOTH_GROUP_REINFORCED_WALLS, SMOOTH_GROUP_AIRLOCK, SMOOTH_GROUP_WINDOW_FULLTILE)
 
 /obj/structure/falsewall
 	icon = 'modular_ss220/aesthetics/walls/icons/wall.dmi'
+	canSmoothWith = list(SMOOTH_GROUP_WALLS, SMOOTH_GROUP_REGULAR_WALLS, SMOOTH_GROUP_REINFORCED_WALLS, SMOOTH_GROUP_AIRLOCK, SMOOTH_GROUP_WINDOW_FULLTILE)
 
 /obj/structure/falsewall/reinforced
 	icon = 'modular_ss220/aesthetics/walls/icons/reinforced_wall.dmi'
+	canSmoothWith = list(SMOOTH_GROUP_WALLS, SMOOTH_GROUP_REGULAR_WALLS, SMOOTH_GROUP_REINFORCED_WALLS, SMOOTH_GROUP_AIRLOCK, SMOOTH_GROUP_WINDOW_FULLTILE)
 
 /turf/simulated/wall/indestructible/riveted
 	icon = 'modular_ss220/aesthetics/walls/icons/reinforced_wall.dmi'
+	canSmoothWith = list(SMOOTH_GROUP_WALLS, SMOOTH_GROUP_REGULAR_WALLS, SMOOTH_GROUP_REINFORCED_WALLS, SMOOTH_GROUP_AIRLOCK, SMOOTH_GROUP_WINDOW_FULLTILE)
+
+/turf/simulated/wall/mineral/titanium
+	smoothing_groups = list(SMOOTH_GROUP_TITANIUM_WALLS)
+	canSmoothWith = list(SMOOTH_GROUP_TITANIUM_WALLS, SMOOTH_GROUP_AIRLOCK, SMOOTH_GROUP_SHUTTLE_PARTS, SMOOTH_GROUP_WINDOW_FULLTILE_SHUTTLE)
+
+/turf/simulated/wall/indestructible/wood
+	smoothing_groups = list(SMOOTH_GROUP_WOOD_WALLS)
+	canSmoothWith = list(SMOOTH_GROUP_WOOD_WALLS, SMOOTH_GROUP_AIRLOCK)
+
diff --git a/modular_ss220/aesthetics/windows/code/windows.dm b/modular_ss220/aesthetics/windows/code/windows.dm
index 9472e6d4ed6c..a083eabb95a0 100644
--- a/modular_ss220/aesthetics/windows/code/windows.dm
+++ b/modular_ss220/aesthetics/windows/code/windows.dm
@@ -1,3 +1,7 @@
+/obj/structure/window/full
+	smoothing_groups = list(SMOOTH_GROUP_WINDOW_FULLTILE)
+	canSmoothWith = list(SMOOTH_GROUP_WINDOW_FULLTILE, SMOOTH_GROUP_WALLS, SMOOTH_GROUP_REINFORCED_WALLS, SMOOTH_GROUP_AIRLOCK)
+
 /obj/structure/window/full/basic
 	icon = 'modular_ss220/aesthetics/windows/icons/window.dmi'
 	edge_overlay_file = 'modular_ss220/aesthetics/windows/icons/window_edges.dmi'
@@ -20,6 +24,12 @@
 /turf/simulated/wall/indestructible/fakeglass
 	icon = 'modular_ss220/aesthetics/windows/icons/reinforced_window.dmi'
 	edge_overlay_file = 'modular_ss220/aesthetics/windows/icons/reinforced_window_edges.dmi'
+	smoothing_groups = list(SMOOTH_GROUP_WINDOW_FULLTILE)
+	canSmoothWith = list(SMOOTH_GROUP_WINDOW_FULLTILE, SMOOTH_GROUP_WALLS, SMOOTH_GROUP_REINFORCED_WALLS, SMOOTH_GROUP_AIRLOCK)
+
+/obj/structure/window/full/shuttle
+	smoothing_groups = list(SMOOTH_GROUP_WINDOW_FULLTILE_SHUTTLE)
+	canSmoothWith = list(SMOOTH_GROUP_WINDOW_FULLTILE_SHUTTLE, SMOOTH_GROUP_TITANIUM_WALLS, SMOOTH_GROUP_AIRLOCK)
 
 //WINDOW SPAWNERS
 /obj/effect/spawner/window