diff --git a/levels/ghost_ship/ghost_ship_level.tscn b/levels/ghost_ship/ghost_ship_level.tscn
index 7f3a132..37ef173 100644
--- a/levels/ghost_ship/ghost_ship_level.tscn
+++ b/levels/ghost_ship/ghost_ship_level.tscn
@@ -6047,7 +6047,7 @@ transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, -12)
 mesh = ExtResource("6_6giaa")
 skeleton = NodePath("../..")
 
-[node name="GunkBody" parent="Airlock/Bounds/Floor" instance=ExtResource("2_2egij")]
+[node name="GunkBody" parent="Airlock/Bounds/Floor" groups=["MetalMaterial"] instance=ExtResource("2_2egij")]
 initial_mask = ExtResource("3_35kna")
 source_gunk_material = SubResource("ShaderMaterial_sqa4l")
 
@@ -6145,7 +6145,7 @@ transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, 2.5, 1.5, 0.1)
 transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, -3.9, 1, -1.5)
 mesh = SubResource("CapsuleMesh_lfacn")
 
-[node name="StaticBody3D" type="StaticBody3D" parent="Airlock/Props/EVASuit"]
+[node name="StaticBody3D" type="StaticBody3D" parent="Airlock/Props/EVASuit" groups=["PlasticMaterial"]]
 collision_layer = 5
 
 [node name="CollisionShape3D" type="CollisionShape3D" parent="Airlock/Props/EVASuit/StaticBody3D"]
@@ -6155,7 +6155,7 @@ shape = SubResource("CapsuleShape3D_lfacn")
 transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, -3.9, 1, 1.5)
 mesh = SubResource("CapsuleMesh_lfacn")
 
-[node name="StaticBody3D" type="StaticBody3D" parent="Airlock/Props/EVASuit2"]
+[node name="StaticBody3D" type="StaticBody3D" parent="Airlock/Props/EVASuit2" groups=["PlasticMaterial"]]
 collision_layer = 5
 
 [node name="CollisionShape3D" type="CollisionShape3D" parent="Airlock/Props/EVASuit2/StaticBody3D"]
@@ -6165,7 +6165,7 @@ shape = SubResource("CapsuleShape3D_lfacn")
 transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, 3.9, 1, 1.5)
 mesh = SubResource("CapsuleMesh_lfacn")
 
-[node name="StaticBody3D" type="StaticBody3D" parent="Airlock/Props/EVASuit3"]
+[node name="StaticBody3D" type="StaticBody3D" parent="Airlock/Props/EVASuit3" groups=["PlasticMaterial"]]
 collision_layer = 5
 
 [node name="CollisionShape3D" type="CollisionShape3D" parent="Airlock/Props/EVASuit3/StaticBody3D"]
@@ -6175,7 +6175,7 @@ shape = SubResource("CapsuleShape3D_lfacn")
 transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, 3.9, 1, -1.5)
 mesh = SubResource("CapsuleMesh_lfacn")
 
-[node name="StaticBody3D" type="StaticBody3D" parent="Airlock/Props/EVASuit4"]
+[node name="StaticBody3D" type="StaticBody3D" parent="Airlock/Props/EVASuit4" groups=["PlasticMaterial"]]
 collision_layer = 5
 
 [node name="CollisionShape3D" type="CollisionShape3D" parent="Airlock/Props/EVASuit4/StaticBody3D"]
@@ -6225,7 +6225,7 @@ transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, -22.5)
 mesh = ExtResource("25_smvh1")
 skeleton = NodePath("Hallway1")
 
-[node name="Hallway1" parent="Corridor1/Hallway1" instance=ExtResource("2_2egij")]
+[node name="Hallway1" parent="Corridor1/Hallway1" groups=["MetalMaterial"] instance=ExtResource("2_2egij")]
 source_gunk_material = SubResource("ShaderMaterial_35kna")
 
 [node name="CollisionShape3D" type="CollisionShape3D" parent="Corridor1/Hallway1/Hallway1"]
@@ -6273,7 +6273,7 @@ transform = Transform3D(-1, 0, 8.74228e-08, 0, 1, 0, -8.74228e-08, 0, -1, 0, 0,
 mesh = ExtResource("27_17ivy")
 skeleton = NodePath("GunkBody")
 
-[node name="GunkBody" parent="Corridor1/T-Junction1" instance=ExtResource("2_2egij")]
+[node name="GunkBody" parent="Corridor1/T-Junction1" groups=["MetalMaterial"] instance=ExtResource("2_2egij")]
 mask_dim = 192
 source_gunk_material = SubResource("ShaderMaterial_4a0u4")
 
@@ -6285,7 +6285,7 @@ transform = Transform3D(-4.37114e-08, 0, 1, 0, 1, 0, -1, 0, -4.37114e-08, -7.5,
 mesh = ExtResource("25_smvh1")
 skeleton = NodePath("GunkBody")
 
-[node name="GunkBody" parent="Corridor1/Hallway2" instance=ExtResource("2_2egij")]
+[node name="GunkBody" parent="Corridor1/Hallway2" groups=["MetalMaterial"] instance=ExtResource("2_2egij")]
 source_gunk_material = SubResource("ShaderMaterial_okeuk")
 
 [node name="CollisionShape3D" type="CollisionShape3D" parent="Corridor1/Hallway2/GunkBody"]
@@ -6326,7 +6326,7 @@ transform = Transform3D(-4.37114e-08, 0, -1, 0, 1, 0, 1, 0, -4.37114e-08, -19.5,
 mesh = ExtResource("31_ji5cn")
 skeleton = NodePath("GunkBody")
 
-[node name="GunkBody" parent="Corridor1/Hallway3" instance=ExtResource("2_2egij")]
+[node name="GunkBody" parent="Corridor1/Hallway3" groups=["MetalMaterial"] instance=ExtResource("2_2egij")]
 source_gunk_material = SubResource("ShaderMaterial_d8p6j")
 
 [node name="CollisionShape3D" type="CollisionShape3D" parent="Corridor1/Hallway3/GunkBody"]
@@ -6350,7 +6350,7 @@ transform = Transform3D(-4.37114e-08, 0, 1, 0, 1, 0, -1, 0, -4.37114e-08, -27, 0
 mesh = ExtResource("28_ji5cn")
 skeleton = NodePath("GunkBody")
 
-[node name="GunkBody" parent="Corridor1/T-Junction2" instance=ExtResource("2_2egij")]
+[node name="GunkBody" parent="Corridor1/T-Junction2" groups=["MetalMaterial"] instance=ExtResource("2_2egij")]
 mask_dim = 192
 source_gunk_material = SubResource("ShaderMaterial_gim1e")
 
@@ -6374,7 +6374,7 @@ transform = Transform3D(-1, 0, -8.74228e-08, 0, 1, 0, 8.74228e-08, 0, -1, -27, 0
 mesh = ExtResource("33_okeuk")
 skeleton = NodePath("GunkBody")
 
-[node name="GunkBody" parent="Corridor1/Hallway4" instance=ExtResource("2_2egij")]
+[node name="GunkBody" parent="Corridor1/Hallway4" groups=["MetalMaterial"] instance=ExtResource("2_2egij")]
 source_gunk_material = SubResource("ShaderMaterial_otfxe")
 
 [node name="CollisionShape3D" type="CollisionShape3D" parent="Corridor1/Hallway4/GunkBody"]
@@ -6415,7 +6415,7 @@ transform = Transform3D(-1, 8.74228e-08, -3.82137e-15, 0, -4.37114e-08, -1, -8.7
 mesh = ExtResource("29_35kna")
 skeleton = NodePath("GunkBody")
 
-[node name="GunkBody" parent="MessHall/Walls/Wall" instance=ExtResource("2_2egij")]
+[node name="GunkBody" parent="MessHall/Walls/Wall" groups=["MetalMaterial"] instance=ExtResource("2_2egij")]
 mask_dim = 64
 source_gunk_material = SubResource("ShaderMaterial_lfacn")
 
@@ -6597,7 +6597,7 @@ transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 5)
 mesh = ExtResource("6_6giaa")
 skeleton = NodePath("GunkBody")
 
-[node name="GunkBody" parent="MessHall/Floors/Floor" instance=ExtResource("2_2egij")]
+[node name="GunkBody" parent="MessHall/Floors/Floor" groups=["MetalMaterial"] instance=ExtResource("2_2egij")]
 source_gunk_material = SubResource("ShaderMaterial_f0xh4")
 
 [node name="CollisionShape3D" type="CollisionShape3D" parent="MessHall/Floors/Floor/GunkBody"]
@@ -6608,7 +6608,7 @@ transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, -9, 0, 5)
 mesh = ExtResource("6_6giaa")
 skeleton = NodePath("GunkBody")
 
-[node name="GunkBody" parent="MessHall/Floors/Floor3" instance=ExtResource("2_2egij")]
+[node name="GunkBody" parent="MessHall/Floors/Floor3" groups=["MetalMaterial"] instance=ExtResource("2_2egij")]
 source_gunk_material = SubResource("ShaderMaterial_kp5n7")
 
 [node name="CollisionShape3D" type="CollisionShape3D" parent="MessHall/Floors/Floor3/GunkBody"]
@@ -6642,7 +6642,7 @@ shape = SubResource("ConcavePolygonShape3D_d1yty")
 transform = Transform3D(0.965926, 0, -0.258819, 0, 1, 0, 0.258819, 0, 0.965926, -2.4, 0.4, 6.2)
 mesh = SubResource("BoxMesh_4a0u4")
 
-[node name="StaticBody3D" type="StaticBody3D" parent="MessHall/Props/Table"]
+[node name="StaticBody3D" type="StaticBody3D" parent="MessHall/Props/Table" groups=["PlasticMaterial"]]
 collision_layer = 5
 
 [node name="CollisionShape3D" type="CollisionShape3D" parent="MessHall/Props/Table/StaticBody3D"]
@@ -6652,7 +6652,7 @@ shape = SubResource("ConcavePolygonShape3D_35kna")
 transform = Transform3D(0.866025, 0, -0.5, 0, 1, 0, 0.5, 0, 0.866025, -7.5, 0.4, 4.1)
 mesh = SubResource("BoxMesh_4a0u4")
 
-[node name="StaticBody3D" type="StaticBody3D" parent="MessHall/Props/Table2"]
+[node name="StaticBody3D" type="StaticBody3D" parent="MessHall/Props/Table2" groups=["PlasticMaterial"]]
 collision_layer = 5
 
 [node name="CollisionShape3D" type="CollisionShape3D" parent="MessHall/Props/Table2/StaticBody3D"]
@@ -6662,7 +6662,7 @@ shape = SubResource("ConcavePolygonShape3D_4a0u4")
 transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, -13, 0.5, 3.5)
 mesh = SubResource("BoxMesh_35kna")
 
-[node name="StaticBody3D" type="StaticBody3D" parent="MessHall/Props/Counter"]
+[node name="StaticBody3D" type="StaticBody3D" parent="MessHall/Props/Counter" groups=["PlasticMaterial"]]
 collision_layer = 5
 
 [node name="CollisionShape3D" type="CollisionShape3D" parent="MessHall/Props/Counter/StaticBody3D"]
@@ -6672,7 +6672,7 @@ shape = SubResource("ConcavePolygonShape3D_okeuk")
 transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, -13, 2.5, 4.5)
 mesh = SubResource("BoxMesh_okeuk")
 
-[node name="StaticBody3D" type="StaticBody3D" parent="MessHall/Props/Cupboard"]
+[node name="StaticBody3D" type="StaticBody3D" parent="MessHall/Props/Cupboard" groups=["PlasticMaterial"]]
 collision_layer = 5
 
 [node name="CollisionShape3D" type="CollisionShape3D" parent="MessHall/Props/Cupboard/StaticBody3D"]
@@ -6682,7 +6682,7 @@ shape = SubResource("ConcavePolygonShape3D_d8p6j")
 transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, -12.8, 1.3, 7.996)
 mesh = SubResource("BoxMesh_d8p6j")
 
-[node name="StaticBody3D" type="StaticBody3D" parent="MessHall/Props/Freezer"]
+[node name="StaticBody3D" type="StaticBody3D" parent="MessHall/Props/Freezer" groups=["MetalMaterial"]]
 collision_layer = 5
 
 [node name="CollisionShape3D" type="CollisionShape3D" parent="MessHall/Props/Freezer/StaticBody3D"]
@@ -6692,7 +6692,7 @@ shape = SubResource("ConcavePolygonShape3D_otfxe")
 transform = Transform3D(-0.422618, -0.906308, -3.69465e-08, -0.906308, 0.422618, -7.92319e-08, 8.74228e-08, 0, -1, 0.481997, 1.19006, 4.7)
 mesh = SubResource("BoxMesh_gim1e")
 
-[node name="StaticBody3D" type="StaticBody3D" parent="MessHall/Props/VendingMachine"]
+[node name="StaticBody3D" type="StaticBody3D" parent="MessHall/Props/VendingMachine" groups=["MetalMaterial"]]
 collision_layer = 5
 
 [node name="CollisionShape3D" type="CollisionShape3D" parent="MessHall/Props/VendingMachine/StaticBody3D"]
@@ -6896,7 +6896,7 @@ transform = Transform3D(-1, 0, 8.74228e-08, 0, 1, 0, -8.74228e-08, 0, -1, 0, 0,
 mesh = ExtResource("33_okeuk")
 skeleton = NodePath("Hallway1")
 
-[node name="Hallway1" parent="Corridor2/Hallway1" instance=ExtResource("2_2egij")]
+[node name="Hallway1" parent="Corridor2/Hallway1" groups=["MetalMaterial"] instance=ExtResource("2_2egij")]
 source_gunk_material = SubResource("ShaderMaterial_ojd88")
 
 [node name="CollisionShape3D" type="CollisionShape3D" parent="Corridor2/Hallway1/Hallway1"]
@@ -6929,7 +6929,7 @@ transform = Transform3D(-4.37114e-08, 0, -1, 0, 1, 0, 1, 0, -4.37114e-08, 7.5, 0
 mesh = ExtResource("25_smvh1")
 skeleton = NodePath("Hallway1")
 
-[node name="Hallway1" parent="Corridor2/Hallway2" instance=ExtResource("2_2egij")]
+[node name="Hallway1" parent="Corridor2/Hallway2" groups=["MetalMaterial"] instance=ExtResource("2_2egij")]
 source_gunk_material = SubResource("ShaderMaterial_anoak")
 
 [node name="CollisionShape3D" type="CollisionShape3D" parent="Corridor2/Hallway2/Hallway1"]
@@ -6962,7 +6962,7 @@ transform = Transform3D(-4.37114e-08, 0, -1, 0, 1, 0, 1, 0, -4.37114e-08, 0, 0,
 mesh = ExtResource("28_ji5cn")
 skeleton = NodePath("GunkBody")
 
-[node name="GunkBody" parent="Corridor2/T-Junction1" instance=ExtResource("2_2egij")]
+[node name="GunkBody" parent="Corridor2/T-Junction1" groups=["MetalMaterial"] instance=ExtResource("2_2egij")]
 mask_dim = 192
 source_gunk_material = SubResource("ShaderMaterial_h1nog")
 
@@ -7003,7 +7003,7 @@ transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, -18, 0, -66)
 mesh = ExtResource("6_6giaa")
 skeleton = NodePath("GunkBody")
 
-[node name="GunkBody" parent="CrewQuarters/CommonArea/Bounds/Floor" instance=ExtResource("2_2egij")]
+[node name="GunkBody" parent="CrewQuarters/CommonArea/Bounds/Floor" groups=["MetalMaterial"] instance=ExtResource("2_2egij")]
 source_gunk_material = SubResource("ShaderMaterial_mgo71")
 
 [node name="CollisionShape3D" type="CollisionShape3D" parent="CrewQuarters/CommonArea/Bounds/Floor/GunkBody"]
@@ -7108,7 +7108,7 @@ shape = SubResource("ConcavePolygonShape3D_lfacn")
 transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0.6, -1.2)
 mesh = SubResource("CylinderMesh_48a1a")
 
-[node name="StaticBody3D" type="StaticBody3D" parent="CrewQuarters/CommonArea/Props/CoffeeTable"]
+[node name="StaticBody3D" type="StaticBody3D" parent="CrewQuarters/CommonArea/Props/CoffeeTable" groups=["PlasticMaterial"]]
 collision_layer = 5
 
 [node name="CollisionShape3D" type="CollisionShape3D" parent="CrewQuarters/CommonArea/Props/CoffeeTable/StaticBody3D"]
@@ -7137,7 +7137,7 @@ transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, -3, 0, -6)
 transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, -3, 0, -1.5)
 mesh = ExtResource("35_6giaa")
 
-[node name="GunkBody" parent="CrewQuarters/Room1/Bounds/Floor" instance=ExtResource("2_2egij")]
+[node name="GunkBody" parent="CrewQuarters/Room1/Bounds/Floor" groups=["MetalMaterial"] instance=ExtResource("2_2egij")]
 source_gunk_material = SubResource("ShaderMaterial_u2hqf")
 
 [node name="CollisionShape3D" type="CollisionShape3D" parent="CrewQuarters/Room1/Bounds/Floor/GunkBody"]
@@ -7285,7 +7285,7 @@ transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, 9, 0, -6)
 transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, -3, 0, -1.5)
 mesh = ExtResource("35_6giaa")
 
-[node name="GunkBody" parent="CrewQuarters/Room2/Bounds/Floor" instance=ExtResource("2_2egij")]
+[node name="GunkBody" parent="CrewQuarters/Room2/Bounds/Floor" groups=["MetalMaterial"] instance=ExtResource("2_2egij")]
 source_gunk_material = SubResource("ShaderMaterial_2ybo5")
 
 [node name="CollisionShape3D" type="CollisionShape3D" parent="CrewQuarters/Room2/Bounds/Floor/GunkBody"]
@@ -7429,7 +7429,7 @@ transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, 9, 0, 9)
 transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, -3, 0, -1.5)
 mesh = ExtResource("35_6giaa")
 
-[node name="GunkBody" parent="CrewQuarters/Room3/Bounds/Floor" instance=ExtResource("2_2egij")]
+[node name="GunkBody" parent="CrewQuarters/Room3/Bounds/Floor" groups=["MetalMaterial"] instance=ExtResource("2_2egij")]
 source_gunk_material = SubResource("ShaderMaterial_lhj8x")
 
 [node name="CollisionShape3D" type="CollisionShape3D" parent="CrewQuarters/Room3/Bounds/Floor/GunkBody"]
@@ -7573,7 +7573,7 @@ transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, -3, 0, 9)
 transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, -3, 0, -1.5)
 mesh = ExtResource("35_6giaa")
 
-[node name="GunkBody" parent="CrewQuarters/Room4/Bounds/Floor" instance=ExtResource("2_2egij")]
+[node name="GunkBody" parent="CrewQuarters/Room4/Bounds/Floor" groups=["MetalMaterial"] instance=ExtResource("2_2egij")]
 source_gunk_material = SubResource("ShaderMaterial_f8ygr")
 
 [node name="CollisionShape3D" type="CollisionShape3D" parent="CrewQuarters/Room4/Bounds/Floor/GunkBody"]
@@ -7722,7 +7722,7 @@ transform = Transform3D(-4.37114e-08, 0, -1, 0, 1, 0, 1, 0, -4.37114e-08, 4.5, 0
 mesh = ExtResource("25_smvh1")
 skeleton = NodePath("Hallway1")
 
-[node name="Hallway1" parent="Corridor3/Hallway" instance=ExtResource("2_2egij")]
+[node name="Hallway1" parent="Corridor3/Hallway" groups=["MetalMaterial"] instance=ExtResource("2_2egij")]
 source_gunk_material = SubResource("ShaderMaterial_0adbo")
 
 [node name="CollisionShape3D" type="CollisionShape3D" parent="Corridor3/Hallway/Hallway1"]
@@ -7755,7 +7755,7 @@ transform = Transform3D(-1, 0, 8.74228e-08, 0, 1, 0, -8.74228e-08, 0, -1, 12, 0,
 mesh = ExtResource("25_smvh1")
 skeleton = NodePath("Hallway1")
 
-[node name="Hallway1" parent="Corridor3/Hallway2" instance=ExtResource("2_2egij")]
+[node name="Hallway1" parent="Corridor3/Hallway2" groups=["MetalMaterial"] instance=ExtResource("2_2egij")]
 source_gunk_material = SubResource("ShaderMaterial_08djo")
 
 [node name="CollisionShape3D" type="CollisionShape3D" parent="Corridor3/Hallway2/Hallway1"]
@@ -7788,7 +7788,7 @@ transform = Transform3D(-1, 0, 8.74228e-08, 0, 1, 0, -8.74228e-08, 0, -1, 12, 0,
 mesh = ExtResource("28_ji5cn")
 skeleton = NodePath("GunkBody")
 
-[node name="GunkBody" parent="Corridor3/T-Junction1" instance=ExtResource("2_2egij")]
+[node name="GunkBody" parent="Corridor3/T-Junction1" groups=["MetalMaterial"] instance=ExtResource("2_2egij")]
 mask_dim = 192
 source_gunk_material = SubResource("ShaderMaterial_yf6ob")
 
@@ -7800,7 +7800,7 @@ transform = Transform3D(-1, 0, 8.74228e-08, 0, 1, 0, -8.74228e-08, 0, -1, 12, 0,
 mesh = ExtResource("25_smvh1")
 skeleton = NodePath("Hallway1")
 
-[node name="Hallway1" parent="Corridor3/Hallway3" instance=ExtResource("2_2egij")]
+[node name="Hallway1" parent="Corridor3/Hallway3" groups=["MetalMaterial"] instance=ExtResource("2_2egij")]
 source_gunk_material = SubResource("ShaderMaterial_8rwkc")
 
 [node name="CollisionShape3D" type="CollisionShape3D" parent="Corridor3/Hallway3/Hallway1"]
@@ -7819,7 +7819,7 @@ transform = Transform3D(1, 0, -2.13163e-14, 0, 1, 0, 2.13163e-14, 0, 1, 12, 0, 1
 mesh = ExtResource("27_17ivy")
 skeleton = NodePath("GunkBody")
 
-[node name="GunkBody" parent="Corridor3/T-Junction2" instance=ExtResource("2_2egij")]
+[node name="GunkBody" parent="Corridor3/T-Junction2" groups=["MetalMaterial"] instance=ExtResource("2_2egij")]
 mask_dim = 192
 source_gunk_material = SubResource("ShaderMaterial_ogcyf")
 
@@ -7831,7 +7831,7 @@ transform = Transform3D(-1, 0, 8.74228e-08, 0, 1, 0, -8.74228e-08, 0, -1, 12, 0,
 mesh = ExtResource("25_smvh1")
 skeleton = NodePath("Hallway1")
 
-[node name="Hallway1" parent="Corridor3/Hallway4" instance=ExtResource("2_2egij")]
+[node name="Hallway1" parent="Corridor3/Hallway4" groups=["MetalMaterial"] instance=ExtResource("2_2egij")]
 source_gunk_material = SubResource("ShaderMaterial_lnif7")
 
 [node name="CollisionShape3D" type="CollisionShape3D" parent="Corridor3/Hallway4/Hallway1"]
@@ -7850,7 +7850,7 @@ transform = Transform3D(-1, 0, -8.74228e-08, 0, 1, 0, 8.74228e-08, 0, -1, 12, 0,
 mesh = ExtResource("27_17ivy")
 skeleton = NodePath("GunkBody")
 
-[node name="GunkBody" parent="Corridor3/T-Junction3" instance=ExtResource("2_2egij")]
+[node name="GunkBody" parent="Corridor3/T-Junction3" groups=["MetalMaterial"] instance=ExtResource("2_2egij")]
 mask_dim = 192
 source_gunk_material = SubResource("ShaderMaterial_gxf7f")
 
@@ -7864,7 +7864,7 @@ transform = Transform3D(-4.37114e-08, 0, 1, 0, 1, 0, -1, 0, -4.37114e-08, 12, 0,
 mesh = ExtResource("35_d8p6j")
 skeleton = NodePath("../..")
 
-[node name="GunkBody" parent="Corridor3/ShortHallway/Floor" instance=ExtResource("2_2egij")]
+[node name="GunkBody" parent="Corridor3/ShortHallway/Floor" groups=["MetalMaterial"] instance=ExtResource("2_2egij")]
 mask_dim = 64
 source_gunk_material = SubResource("ShaderMaterial_ffr5l")
 
@@ -7915,7 +7915,7 @@ transform = Transform3D(-1, 0, -8.74228e-08, 0, 1, 0, 8.74228e-08, 0, -1, 0, 0,
 mesh = ExtResource("35_d8p6j")
 skeleton = NodePath("../..")
 
-[node name="GunkBody" parent="Corridor3/ShortHallway2/Floor" instance=ExtResource("2_2egij")]
+[node name="GunkBody" parent="Corridor3/ShortHallway2/Floor" groups=["MetalMaterial"] instance=ExtResource("2_2egij")]
 mask_dim = 64
 source_gunk_material = SubResource("ShaderMaterial_wnuyc")
 
@@ -7965,7 +7965,7 @@ transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, 6, 0, 30)
 mesh = ExtResource("35_d8p6j")
 skeleton = NodePath("../..")
 
-[node name="GunkBody" parent="Corridor3/ShortHallway3/Floor" instance=ExtResource("2_2egij")]
+[node name="GunkBody" parent="Corridor3/ShortHallway3/Floor" groups=["MetalMaterial"] instance=ExtResource("2_2egij")]
 mask_dim = 64
 source_gunk_material = SubResource("ShaderMaterial_38po5")
 
@@ -8030,7 +8030,7 @@ transform = Transform3D(-1, 0, -8.74228e-08, 0, 1, 0, 8.74228e-08, 0, -1, 0, 0,
 mesh = ExtResource("35_d8p6j")
 skeleton = NodePath("../..")
 
-[node name="GunkBody" parent="Corridor3/ShortHallway4/Floor" instance=ExtResource("2_2egij")]
+[node name="GunkBody" parent="Corridor3/ShortHallway4/Floor" groups=["MetalMaterial"] instance=ExtResource("2_2egij")]
 mask_dim = 64
 source_gunk_material = SubResource("ShaderMaterial_341fj")
 
@@ -8080,7 +8080,7 @@ transform = Transform3D(-1, 0, 8.74228e-08, 0, 1, 0, -8.74228e-08, 0, -1, -6, 0,
 mesh = ExtResource("35_d8p6j")
 skeleton = NodePath("../..")
 
-[node name="GunkBody" parent="Corridor3/ShortHallway5/Floor" instance=ExtResource("2_2egij")]
+[node name="GunkBody" parent="Corridor3/ShortHallway5/Floor" groups=["MetalMaterial"] instance=ExtResource("2_2egij")]
 mask_dim = 64
 source_gunk_material = SubResource("ShaderMaterial_2yyyp")
 
@@ -8130,7 +8130,7 @@ transform = Transform3D(-1, 0, -8.74228e-08, 0, 1, 0, 8.74228e-08, 0, -1, 15, 0,
 mesh = ExtResource("35_d8p6j")
 skeleton = NodePath("../..")
 
-[node name="GunkBody" parent="Corridor3/ShortHallway6/Floor" instance=ExtResource("2_2egij")]
+[node name="GunkBody" parent="Corridor3/ShortHallway6/Floor" groups=["MetalMaterial"] instance=ExtResource("2_2egij")]
 mask_dim = 64
 source_gunk_material = SubResource("ShaderMaterial_6ypgw")
 
@@ -8200,7 +8200,7 @@ transform = Transform3D(-4.37114e-08, 0, -1, 0, 1, 0, 1, 0, -4.37114e-08, 0, 0,
 mesh = ExtResource("6_6giaa")
 skeleton = NodePath("GunkBody")
 
-[node name="GunkBody" parent="Medbay/Bounds/Floor" instance=ExtResource("2_2egij")]
+[node name="GunkBody" parent="Medbay/Bounds/Floor" groups=["MetalMaterial"] instance=ExtResource("2_2egij")]
 source_gunk_material = SubResource("ShaderMaterial_20tdk")
 
 [node name="CollisionShape3D" type="CollisionShape3D" parent="Medbay/Bounds/Floor/GunkBody"]
@@ -8211,7 +8211,7 @@ transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, -9, 0, 3.93402e-07)
 mesh = ExtResource("6_6giaa")
 skeleton = NodePath("GunkBody")
 
-[node name="GunkBody" parent="Medbay/Bounds/Floor2" instance=ExtResource("2_2egij")]
+[node name="GunkBody" parent="Medbay/Bounds/Floor2" groups=["MetalMaterial"] instance=ExtResource("2_2egij")]
 source_gunk_material = SubResource("ShaderMaterial_6s0nd")
 
 [node name="CollisionShape3D" type="CollisionShape3D" parent="Medbay/Bounds/Floor2/GunkBody"]
@@ -8437,7 +8437,7 @@ shape = SubResource("ConcavePolygonShape3D_p11ap")
 transform = Transform3D(-1, 0, -1.74846e-07, 0, 1, 0, 8.74228e-08, 0, -2, 0, 1, -0.299999)
 mesh = SubResource("CylinderMesh_f0xh4")
 
-[node name="StaticBody3D" type="StaticBody3D" parent="Medbay/Props/OperatingTable"]
+[node name="StaticBody3D" type="StaticBody3D" parent="Medbay/Props/OperatingTable" groups=["MetalMaterial"]]
 collision_layer = 5
 
 [node name="CollisionShape3D" type="CollisionShape3D" parent="Medbay/Props/OperatingTable/StaticBody3D"]
@@ -8452,7 +8452,7 @@ transform = Transform3D(0.707107, 0, -0.707107, 0, 1, 0, 0.707107, 0, 0.707107,
 mesh = SubResource("BoxMesh_1h5r5")
 skeleton = NodePath("../..")
 
-[node name="StaticBody3D" type="StaticBody3D" parent="Medbay/Props/Desk"]
+[node name="StaticBody3D" type="StaticBody3D" parent="Medbay/Props/Desk" groups=["PlasticMaterial"]]
 collision_layer = 5
 
 [node name="CollisionShape3D" type="CollisionShape3D" parent="Medbay/Props/Desk/StaticBody3D"]
@@ -8466,7 +8466,7 @@ shape = SubResource("ConcavePolygonShape3D_2qkxu")
 transform = Transform3D(-0.24869, 0, 0.968583, 0, 1, 0, -0.968583, 0, -0.24869, -1.8, 0.6, 0)
 mesh = SubResource("BoxMesh_ii88q")
 
-[node name="StaticBody3D" type="StaticBody3D" parent="Medbay/Props/Cart"]
+[node name="StaticBody3D" type="StaticBody3D" parent="Medbay/Props/Cart" groups=["PlasticMaterial"]]
 collision_layer = 5
 
 [node name="CollisionShape3D" type="CollisionShape3D" parent="Medbay/Props/Cart/StaticBody3D"]
@@ -8476,7 +8476,7 @@ shape = SubResource("ConcavePolygonShape3D_wvfch")
 transform = Transform3D(0.00523592, -0.866025, 0.499973, -0.999945, -4.2222e-08, 0.0104718, -0.00906879, -0.5, -0.865978, -3.3, 0.355217, -0.599998)
 mesh = SubResource("BoxMesh_ii88q")
 
-[node name="StaticBody3D" type="StaticBody3D" parent="Medbay/Props/Cart2"]
+[node name="StaticBody3D" type="StaticBody3D" parent="Medbay/Props/Cart2" groups=["PlasticMaterial"]]
 collision_layer = 5
 
 [node name="CollisionShape3D" type="CollisionShape3D" parent="Medbay/Props/Cart2/StaticBody3D"]
@@ -8486,7 +8486,7 @@ shape = SubResource("ConcavePolygonShape3D_wvfch")
 transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, -3.3, 0.6, 3.9)
 mesh = SubResource("BoxMesh_ii88q")
 
-[node name="StaticBody3D" type="StaticBody3D" parent="Medbay/Props/Cart3"]
+[node name="StaticBody3D" type="StaticBody3D" parent="Medbay/Props/Cart3" groups=["PlasticMaterial"]]
 collision_layer = 5
 
 [node name="CollisionShape3D" type="CollisionShape3D" parent="Medbay/Props/Cart3/StaticBody3D"]
@@ -8496,7 +8496,7 @@ shape = SubResource("ConcavePolygonShape3D_wvfch")
 transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, -2.4, 0.6, 3.9)
 mesh = SubResource("BoxMesh_ii88q")
 
-[node name="StaticBody3D" type="StaticBody3D" parent="Medbay/Props/Cart4"]
+[node name="StaticBody3D" type="StaticBody3D" parent="Medbay/Props/Cart4" groups=["PlasticMaterial"]]
 collision_layer = 5
 
 [node name="CollisionShape3D" type="CollisionShape3D" parent="Medbay/Props/Cart4/StaticBody3D"]
@@ -8506,7 +8506,7 @@ shape = SubResource("ConcavePolygonShape3D_wvfch")
 transform = Transform3D(0.965926, 0, -0.258819, 0, 1, 0, 0.258819, 0, 0.965926, -1.2, 0.6, 3.9)
 mesh = SubResource("BoxMesh_ii88q")
 
-[node name="StaticBody3D" type="StaticBody3D" parent="Medbay/Props/Cart5"]
+[node name="StaticBody3D" type="StaticBody3D" parent="Medbay/Props/Cart5" groups=["PlasticMaterial"]]
 collision_layer = 5
 
 [node name="CollisionShape3D" type="CollisionShape3D" parent="Medbay/Props/Cart5/StaticBody3D"]
@@ -8516,7 +8516,7 @@ shape = SubResource("ConcavePolygonShape3D_wvfch")
 transform = Transform3D(0.866025, 0, 0.5, 0, 1, 0, -0.5, 0, 0.866025, 1.2, 0.6, -3.3)
 mesh = SubResource("BoxMesh_ii88q")
 
-[node name="StaticBody3D" type="StaticBody3D" parent="Medbay/Props/MonitorCart"]
+[node name="StaticBody3D" type="StaticBody3D" parent="Medbay/Props/MonitorCart" groups=["PlasticMaterial"]]
 collision_layer = 5
 
 [node name="CollisionShape3D" type="CollisionShape3D" parent="Medbay/Props/MonitorCart/StaticBody3D"]
@@ -8534,7 +8534,7 @@ mesh = SubResource("PrismMesh_8r2kq")
 transform = Transform3D(1, 0, -2.98023e-08, 0, 1, 0, 2.98023e-08, 0, 1, 3.9, 0.6, -8.1)
 mesh = SubResource("BoxMesh_ii88q")
 
-[node name="StaticBody3D" type="StaticBody3D" parent="Medbay/Props/MonitorCart2"]
+[node name="StaticBody3D" type="StaticBody3D" parent="Medbay/Props/MonitorCart2" groups=["PlasticMaterial"]]
 collision_layer = 5
 
 [node name="CollisionShape3D" type="CollisionShape3D" parent="Medbay/Props/MonitorCart2/StaticBody3D"]
@@ -8552,7 +8552,7 @@ mesh = SubResource("PrismMesh_8r2kq")
 transform = Transform3D(1, 0, -2.98023e-08, 0, 1, 0, 2.98023e-08, 0, 1, 3.9, 0.6, -6.9)
 mesh = SubResource("BoxMesh_ii88q")
 
-[node name="StaticBody3D" type="StaticBody3D" parent="Medbay/Props/MonitorCart3"]
+[node name="StaticBody3D" type="StaticBody3D" parent="Medbay/Props/MonitorCart3" groups=["PlasticMaterial"]]
 collision_layer = 5
 
 [node name="CollisionShape3D" type="CollisionShape3D" parent="Medbay/Props/MonitorCart3/StaticBody3D"]
@@ -8570,7 +8570,7 @@ mesh = SubResource("PrismMesh_8r2kq")
 transform = Transform3D(-4.37114e-08, 0, 1, 0, 1, 0, -1, 0, -4.37114e-08, 1.5, 0.5, -13)
 mesh = SubResource("BoxMesh_35kna")
 
-[node name="StaticBody3D" type="StaticBody3D" parent="Medbay/Props/Counter"]
+[node name="StaticBody3D" type="StaticBody3D" parent="Medbay/Props/Counter" groups=["PlasticMaterial"]]
 collision_layer = 5
 
 [node name="CollisionShape3D" type="CollisionShape3D" parent="Medbay/Props/Counter/StaticBody3D"]
@@ -8580,7 +8580,7 @@ shape = SubResource("ConcavePolygonShape3D_okeuk")
 transform = Transform3D(-4.37114e-08, 0, 1, 0, 1, 0, -1, 0, -4.37114e-08, 2.5, 2.5, -13)
 mesh = SubResource("BoxMesh_okeuk")
 
-[node name="StaticBody3D" type="StaticBody3D" parent="Medbay/Props/Cupboard"]
+[node name="StaticBody3D" type="StaticBody3D" parent="Medbay/Props/Cupboard" groups=["PlasticMaterial"]]
 collision_layer = 5
 
 [node name="CollisionShape3D" type="CollisionShape3D" parent="Medbay/Props/Cupboard/StaticBody3D"]
@@ -8590,7 +8590,7 @@ shape = SubResource("ConcavePolygonShape3D_d8p6j")
 transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, -4, 0.5, -7.5)
 mesh = SubResource("BoxMesh_35kna")
 
-[node name="StaticBody3D" type="StaticBody3D" parent="Medbay/Props/Counter2"]
+[node name="StaticBody3D" type="StaticBody3D" parent="Medbay/Props/Counter2" groups=["PlasticMaterial"]]
 collision_layer = 5
 
 [node name="CollisionShape3D" type="CollisionShape3D" parent="Medbay/Props/Counter2/StaticBody3D"]
@@ -8600,7 +8600,7 @@ shape = SubResource("ConcavePolygonShape3D_okeuk")
 transform = Transform3D(1, 0, 0, 0, 0.965926, -0.258819, 0, 0.258819, 0.965926, -4, 2.02276, -8.6)
 mesh = SubResource("BoxMesh_okeuk")
 
-[node name="StaticBody3D" type="StaticBody3D" parent="Medbay/Props/Cupboard2"]
+[node name="StaticBody3D" type="StaticBody3D" parent="Medbay/Props/Cupboard2" groups=["PlasticMaterial"]]
 collision_layer = 5
 
 [node name="CollisionShape3D" type="CollisionShape3D" parent="Medbay/Props/Cupboard2/StaticBody3D"]
@@ -8681,7 +8681,7 @@ transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, 0, -3, 0)
 mesh = ExtResource("6_6giaa")
 skeleton = NodePath("GunkBody")
 
-[node name="GunkBody" parent="OpsCenter/Bounds/Floor" instance=ExtResource("2_2egij")]
+[node name="GunkBody" parent="OpsCenter/Bounds/Floor" groups=["MetalMaterial"] instance=ExtResource("2_2egij")]
 source_gunk_material = SubResource("ShaderMaterial_45wwf")
 
 [node name="CollisionShape3D" type="CollisionShape3D" parent="OpsCenter/Bounds/Floor/GunkBody"]
@@ -8692,7 +8692,7 @@ transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, -9, -3, 3.93403e-07)
 mesh = ExtResource("6_6giaa")
 skeleton = NodePath("GunkBody")
 
-[node name="GunkBody" parent="OpsCenter/Bounds/Floor2" instance=ExtResource("2_2egij")]
+[node name="GunkBody" parent="OpsCenter/Bounds/Floor2" groups=["MetalMaterial"] instance=ExtResource("2_2egij")]
 source_gunk_material = SubResource("ShaderMaterial_r5lvr")
 
 [node name="CollisionShape3D" type="CollisionShape3D" parent="OpsCenter/Bounds/Floor2/GunkBody"]
@@ -9145,7 +9145,7 @@ transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, 3, 0, -1.31134e-07)
 mesh = ExtResource("35_d8p6j")
 skeleton = NodePath("../..")
 
-[node name="GunkBody" parent="OpsCenter/Bounds/Floor3" instance=ExtResource("2_2egij")]
+[node name="GunkBody" parent="OpsCenter/Bounds/Floor3" groups=["MetalMaterial"] instance=ExtResource("2_2egij")]
 mask_dim = 64
 source_gunk_material = SubResource("ShaderMaterial_p73n1")
 
@@ -9157,7 +9157,7 @@ transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, 3, 0, -3)
 mesh = ExtResource("35_d8p6j")
 skeleton = NodePath("../..")
 
-[node name="GunkBody" parent="OpsCenter/Bounds/Floor4" instance=ExtResource("2_2egij")]
+[node name="GunkBody" parent="OpsCenter/Bounds/Floor4" groups=["MetalMaterial"] instance=ExtResource("2_2egij")]
 mask_dim = 64
 source_gunk_material = SubResource("ShaderMaterial_i0yw4")
 
@@ -9169,7 +9169,7 @@ transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, -3)
 mesh = ExtResource("35_d8p6j")
 skeleton = NodePath("../..")
 
-[node name="GunkBody" parent="OpsCenter/Bounds/Floor5" instance=ExtResource("2_2egij")]
+[node name="GunkBody" parent="OpsCenter/Bounds/Floor5" groups=["MetalMaterial"] instance=ExtResource("2_2egij")]
 mask_dim = 64
 source_gunk_material = SubResource("ShaderMaterial_65lip")
 
@@ -9181,7 +9181,7 @@ transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, -3, 0, -3)
 mesh = ExtResource("35_d8p6j")
 skeleton = NodePath("../..")
 
-[node name="GunkBody" parent="OpsCenter/Bounds/Floor6" instance=ExtResource("2_2egij")]
+[node name="GunkBody" parent="OpsCenter/Bounds/Floor6" groups=["MetalMaterial"] instance=ExtResource("2_2egij")]
 mask_dim = 64
 source_gunk_material = SubResource("ShaderMaterial_leujp")
 
@@ -9193,7 +9193,7 @@ transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, -6, 0, -3)
 mesh = ExtResource("35_d8p6j")
 skeleton = NodePath("../..")
 
-[node name="GunkBody" parent="OpsCenter/Bounds/Floor7" instance=ExtResource("2_2egij")]
+[node name="GunkBody" parent="OpsCenter/Bounds/Floor7" groups=["MetalMaterial"] instance=ExtResource("2_2egij")]
 mask_dim = 64
 source_gunk_material = SubResource("ShaderMaterial_w6td3")
 
@@ -9205,7 +9205,7 @@ transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, -9, 0, -3)
 mesh = ExtResource("35_d8p6j")
 skeleton = NodePath("../..")
 
-[node name="GunkBody" parent="OpsCenter/Bounds/Floor8" instance=ExtResource("2_2egij")]
+[node name="GunkBody" parent="OpsCenter/Bounds/Floor8" groups=["MetalMaterial"] instance=ExtResource("2_2egij")]
 mask_dim = 64
 source_gunk_material = SubResource("ShaderMaterial_5v7i8")
 
@@ -9217,7 +9217,7 @@ transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, -12, 0, -3)
 mesh = ExtResource("35_d8p6j")
 skeleton = NodePath("../..")
 
-[node name="GunkBody" parent="OpsCenter/Bounds/Floor9" instance=ExtResource("2_2egij")]
+[node name="GunkBody" parent="OpsCenter/Bounds/Floor9" groups=["MetalMaterial"] instance=ExtResource("2_2egij")]
 mask_dim = 64
 source_gunk_material = SubResource("ShaderMaterial_pdhq3")
 
@@ -9229,7 +9229,7 @@ transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, -12, 0, 1.23979e-06)
 mesh = ExtResource("35_d8p6j")
 skeleton = NodePath("../..")
 
-[node name="GunkBody" parent="OpsCenter/Bounds/Floor10" instance=ExtResource("2_2egij")]
+[node name="GunkBody" parent="OpsCenter/Bounds/Floor10" groups=["MetalMaterial"] instance=ExtResource("2_2egij")]
 mask_dim = 64
 source_gunk_material = SubResource("ShaderMaterial_ypwsq")
 
@@ -9241,7 +9241,7 @@ transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, -12, 0, 3)
 mesh = ExtResource("35_d8p6j")
 skeleton = NodePath("../..")
 
-[node name="GunkBody" parent="OpsCenter/Bounds/Floor11" instance=ExtResource("2_2egij")]
+[node name="GunkBody" parent="OpsCenter/Bounds/Floor11" groups=["MetalMaterial"] instance=ExtResource("2_2egij")]
 mask_dim = 64
 source_gunk_material = SubResource("ShaderMaterial_kqkqc")
 
@@ -9253,7 +9253,7 @@ transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, 3, 0, 3)
 mesh = ExtResource("35_d8p6j")
 skeleton = NodePath("../..")
 
-[node name="GunkBody" parent="OpsCenter/Bounds/Floor12" instance=ExtResource("2_2egij")]
+[node name="GunkBody" parent="OpsCenter/Bounds/Floor12" groups=["MetalMaterial"] instance=ExtResource("2_2egij")]
 mask_dim = 64
 source_gunk_material = SubResource("ShaderMaterial_p8nhf")
 
@@ -9388,7 +9388,7 @@ transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, -4.5, 0, 2.38419e-07)
 mesh = SubResource("ArrayMesh_pifep")
 skeleton = NodePath("../..")
 
-[node name="GunkBody" parent="OpsCenter/Bounds/Ramp/Floor" instance=ExtResource("2_2egij")]
+[node name="GunkBody" parent="OpsCenter/Bounds/Ramp/Floor" groups=["MetalMaterial"] instance=ExtResource("2_2egij")]
 source_gunk_material = SubResource("ShaderMaterial_08dfj")
 
 [node name="CollisionShape3D" type="CollisionShape3D" parent="OpsCenter/Bounds/Ramp/Floor/GunkBody"]
diff --git a/project.godot b/project.godot
index 24c4e14..9156811 100644
--- a/project.godot
+++ b/project.godot
@@ -72,6 +72,11 @@ audio/buses/override_bus_layout="user://audio_bus_layout.tres"
 config/accessibility/enable_screen_shake=true
 config/accessibility/enable_head_bob=true
 
+[global_group]
+
+MetalMaterial="This surface is made of metal."
+PlasticMaterial="This surface is made of plastic."
+
 [input]
 
 move_forward={
diff --git a/src/player/footsteps/foot_controller.gd b/src/player/footsteps/foot_controller.gd
index c12fa36..6c54bce 100644
--- a/src/player/footsteps/foot_controller.gd
+++ b/src/player/footsteps/foot_controller.gd
@@ -1,23 +1,16 @@
 class_name FootController extends Node3D
 
-enum SurfaceMaterial {
-	UNKNOWN,
-	GRUNK,
-	PLASTIC,
-	METAL,
-}
-
 @onready var metal: AudioStreamPlayer3D = $Metal
 
 
-func get_player_for_material(surface_material: SurfaceMaterial) -> AudioStreamPlayer3D:
+func get_player_for_material(surface_material: SurfaceMaterial.Type) -> AudioStreamPlayer3D:
 	match surface_material:
-		SurfaceMaterial.GRUNK:
+		SurfaceMaterial.Type.GRUNK:
 			pass  # TODO
-		SurfaceMaterial.PLASTIC:
+		SurfaceMaterial.Type.PLASTIC:
 			pass  # TODO
-		SurfaceMaterial.METAL:
+		SurfaceMaterial.Type.METAL:
 			return metal
-		SurfaceMaterial.UNKNOWN:
+		SurfaceMaterial.Type.UNKNOWN:
 			pass
 	return null
diff --git a/src/player/footsteps/footstep_controller.gd b/src/player/footsteps/footstep_controller.gd
index 41110ce..1bc47d3 100644
--- a/src/player/footsteps/footstep_controller.gd
+++ b/src/player/footsteps/footstep_controller.gd
@@ -11,6 +11,8 @@ var _on_right_foot := false
 @onready var left_foot: FootController = %LeftFoot
 @onready var right_foot: FootController = %RightFoot
 
+@onready var foot_cast: RayCast3D = %FootCast
+
 
 func play_footstep() -> void:
 	var foot := right_foot if _on_right_foot else left_foot
@@ -19,9 +21,20 @@ func play_footstep() -> void:
 	if relative_speed < 0:
 		return
 
-	# TODO: detect surface material
-	var sfx := foot.get_player_for_material(FootController.SurfaceMaterial.METAL)
-	sfx.volume_db = BASE_VOLUME + relative_speed * VELOCITY_FACTOR
-	sfx.play()
+	var sfx := foot.get_player_for_material(get_material_under_foot())
+	if sfx:
+		sfx.volume_db = BASE_VOLUME + relative_speed * VELOCITY_FACTOR
+		sfx.play()
 
 	_on_right_foot = not _on_right_foot
+
+
+func get_material_under_foot() -> SurfaceMaterial.Type:
+	var collider := foot_cast.get_collider() as Node
+	if collider is GunkBody:
+		# Special case: check if collision surface is gunked
+		if (collider as GunkBody).is_point_gunked(
+			foot_cast.get_collision_point(), foot_cast.get_collision_normal()
+		):
+			return SurfaceMaterial.Type.GRUNK
+	return SurfaceMaterial.material_for_collider(collider)
diff --git a/src/player/player.tscn b/src/player/player.tscn
index d97a2d0..dec2e76 100644
--- a/src/player/player.tscn
+++ b/src/player/player.tscn
@@ -276,3 +276,7 @@ script = ExtResource("9_l271a")
 stream = SubResource("AudioStreamRandomizer_ylhto")
 volume_db = -42.0
 bus = &"SFX"
+
+[node name="FootCast" type="RayCast3D" parent="FootstepController"]
+unique_name_in_owner = true
+transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0.0518835, 0)
diff --git a/src/props/bulkhead/bulkhead.tscn b/src/props/bulkhead/bulkhead.tscn
index e528d30..402adff 100644
--- a/src/props/bulkhead/bulkhead.tscn
+++ b/src/props/bulkhead/bulkhead.tscn
@@ -319,7 +319,7 @@ script = ExtResource("2_hknvo")
 [node name="Frame" parent="." index="0"]
 mesh = SubResource("ArrayMesh_88aga")
 
-[node name="StaticBody3D" type="StaticBody3D" parent="Frame" index="0"]
+[node name="StaticBody3D" type="StaticBody3D" parent="Frame" index="0" groups=["MetalMaterial"]]
 collision_layer = 5
 
 [node name="CollisionShape3D" type="CollisionShape3D" parent="Frame/StaticBody3D" index="0"]
@@ -328,7 +328,7 @@ shape = SubResource("ConcavePolygonShape3D_88qrs")
 [node name="Door" parent="." index="1"]
 mesh = SubResource("ArrayMesh_bso71")
 
-[node name="StaticBody3D" type="StaticBody3D" parent="Door" index="0"]
+[node name="StaticBody3D" type="StaticBody3D" parent="Door" index="0" groups=["MetalMaterial"]]
 collision_layer = 5
 
 [node name="CollisionShape3D" type="CollisionShape3D" parent="Door/StaticBody3D" index="0"]
@@ -340,7 +340,7 @@ transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 2.9, 0)
 stream = ExtResource("5_4jho1")
 volume_db = -10.0
 
-[node name="Ramp" type="StaticBody3D" parent="." index="4"]
+[node name="Ramp" type="StaticBody3D" parent="." index="4" groups=["MetalMaterial"]]
 
 [node name="MeshInstance3D" type="MeshInstance3D" parent="Ramp" index="0"]
 transform = Transform3D(-4.37114e-08, 0, 1, 0, 1, 0, -1, 0, -4.37114e-08, 0, 0.1, 0.325)
diff --git a/src/props/crate_long/crate_long.tscn b/src/props/crate_long/crate_long.tscn
index 7d15be5..c29a5a8 100644
--- a/src/props/crate_long/crate_long.tscn
+++ b/src/props/crate_long/crate_long.tscn
@@ -101,7 +101,7 @@ data = PackedVector3Array(0.375, -0.15, 0.75, 0.275, -0.25, 0.75, 0.375, 0.15, 0
 [node name="CrateLong" type="MeshInstance3D"]
 mesh = SubResource("ArrayMesh_c6a2t")
 
-[node name="GunkBody" parent="." instance=ExtResource("5_d06p6")]
+[node name="GunkBody" parent="." groups=["PlasticMaterial"] instance=ExtResource("5_d06p6")]
 mask_dim = 32
 source_gunk_material = SubResource("ShaderMaterial_sawbt")
 
diff --git a/src/world/gunk_body/gunk_body.gd b/src/world/gunk_body/gunk_body.gd
index 01364d0..7c7a2c6 100644
--- a/src/world/gunk_body/gunk_body.gd
+++ b/src/world/gunk_body/gunk_body.gd
@@ -10,6 +10,7 @@ const FACE_EPSILON := 0.01
 const CLEAR_COLOR := Color.BLACK
 const MASK_COLOR := Color.RED
 const CLEAR_TOTAL_EPSILON := 1
+const MASK_THRESHOLD := 0.5
 
 @export var mask_dim := 256
 @export var mesh_instance: MeshInstance3D
@@ -30,6 +31,7 @@ var _prev_clear_total := -1.0
 
 # _clear_total is async computed in separate thread
 var _mask_tx: Texture2D
+var _cached_mask: Image
 var _thread: Thread
 var _mutex: Mutex = Mutex.new()
 var _semaphore: Semaphore = Semaphore.new()
@@ -98,10 +100,10 @@ func _async_compute_clear_total() -> void:
 		# Get mask from GPU
 		# TODO: does this need mutex protection?
 		_mutex.lock()
-		var mask_img := _mask_tx.get_image()
+		_cached_mask = _mask_tx.get_image()
+		_cached_mask.convert(Image.FORMAT_R8)
 		_mutex.unlock()
-		mask_img.convert(Image.FORMAT_R8)
-		var px_data := mask_img.get_data()
+		var px_data := _cached_mask.get_data()
 		var px_sum := 0
 		for px in px_data:
 			px_sum += px
@@ -191,6 +193,17 @@ func _get_px(point: Vector3, normal: Vector3) -> Vector2:
 	return _get_uv(point * global_transform, normal * global_basis) * mask_control.size
 
 
+func is_point_gunked(point: Vector3, normal: Vector3) -> bool:
+	var px := _get_px(point, normal)
+	var result := false
+	# XXX deadlock potential?
+	_mutex.lock()
+	result = _cached_mask and _cached_mask.get_pixelv(px).r < MASK_THRESHOLD
+	_mutex.unlock()
+
+	return result
+
+
 ## Paint a dot on the gunk mask.
 func paint_dot(point: Vector3, normal: Vector3, radius: float, color: Color = MASK_COLOR) -> void:
 	var px := _get_px(point, normal)
diff --git a/src/world/surface_material.gd b/src/world/surface_material.gd
new file mode 100644
index 0000000..78c3635
--- /dev/null
+++ b/src/world/surface_material.gd
@@ -0,0 +1,21 @@
+class_name SurfaceMaterial
+
+enum Type {
+	UNKNOWN,
+	GRUNK,
+	PLASTIC,
+	METAL,
+}
+
+const METAL_MATERIAL_GROUP := "MetalMaterial"
+const PLASTIC_MATERIAL_GROUP := "PlasticMaterial"
+
+
+static func material_for_collider(collider: Node) -> SurfaceMaterial.Type:
+	if collider is GunkNode:
+		return Type.GRUNK
+	if collider.is_in_group(METAL_MATERIAL_GROUP):
+		return Type.METAL
+	if collider.is_in_group(PLASTIC_MATERIAL_GROUP):
+		return Type.PLASTIC
+	return Type.UNKNOWN
diff --git a/src/world/surface_material.gd.uid b/src/world/surface_material.gd.uid
new file mode 100644
index 0000000..b0c55c8
--- /dev/null
+++ b/src/world/surface_material.gd.uid
@@ -0,0 +1 @@
+uid://cpr406vyaxxge
diff --git a/vault/TODO.md b/vault/TODO.md
index cf1da79..2235e8f 100644
--- a/vault/TODO.md
+++ b/vault/TODO.md
@@ -54,9 +54,9 @@
 		- [x] beam noises
 		- [x] spray noises
 		- [ ] switch klaxon
-		- [ ] switch OK
+		- [x] switch OK
 		- [ ] switch activation
-		- [ ] bulkhead opening
+		- [x] bulkhead opening
 		- [ ] grunk alarm shriek
 		- [ ] grunk relay chitter
 		- [ ] grunk chittering