diff --git a/src/functionalTest/java/codechicken/multipart/test/DefaultContentFunctionalTest.java b/src/functionalTest/java/codechicken/multipart/test/DefaultContentFunctionalTest.java
index acc730f..fd5a8dd 100644
--- a/src/functionalTest/java/codechicken/multipart/test/DefaultContentFunctionalTest.java
+++ b/src/functionalTest/java/codechicken/multipart/test/DefaultContentFunctionalTest.java
@@ -3,6 +3,7 @@ package codechicken.multipart.test;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertSame;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.lang.reflect.Field;
 import java.util.ArrayList;
@@ -19,21 +20,28 @@ import net.minecraft.init.Blocks;
 
 import org.junit.jupiter.api.Test;
 
+import codechicken.lib.vec.Cuboid6;
 import codechicken.microblock.BlockMicroMaterial;
 import codechicken.microblock.CommonMicroClass;
 import codechicken.microblock.CornerMicroClass$;
 import codechicken.microblock.EdgeMicroClass$;
+import codechicken.microblock.FaceMicroClass;
 import codechicken.microblock.FaceMicroClass$;
+import codechicken.microblock.FaceMicroblock;
+import codechicken.microblock.FacePlacement$;
+import codechicken.microblock.FacePlacementGrid$;
 import codechicken.microblock.GrassMicroMaterial;
 import codechicken.microblock.HollowMicroClass$;
 import codechicken.microblock.MicroMaterialRegistry;
 import codechicken.microblock.MicroMaterialRegistry.IMicroMaterial;
+import codechicken.microblock.Microblock;
 import codechicken.microblock.MissingMicroMaterial;
 import codechicken.microblock.MissingMicroMaterial$;
 import codechicken.microblock.PostMicroClass$;
 import codechicken.microblock.TopMicroMaterial;
 import codechicken.multipart.MultiPartRegistry;
 import codechicken.multipart.MultiPartRegistry.IPartFactory2;
+import codechicken.multipart.TFacePart;
 import scala.Tuple2;
 
 class DefaultContentFunctionalTest {
@@ -71,6 +79,46 @@ class DefaultContentFunctionalTest {
         assertSame(PostMicroClass$.MODULE$, factories.get("mcr_post"));
     }
 
+    @Test
+    void keepsFaceFactoryPlacementAndAllFortyTwoBounds() {
+        FaceMicroClass$ factory = FaceMicroClass$.MODULE$;
+        assertSame(factory, FacePlacement$.MODULE$.microClass());
+        assertSame(FacePlacementGrid$.MODULE$, FacePlacement$.MODULE$.placementGrid());
+        assertSame(factory.aBounds(), FaceMicroClass.aBounds());
+        assertEquals("mcr_face", factory.getName());
+        assertEquals(3, factory.itemSlot());
+        assertEquals(1f, factory.getResistanceFactor());
+
+        Cuboid6[] bounds = factory.aBounds();
+        assertEquals(256, bounds.length);
+        int populated = 0;
+        for (int side = 0; side < 6; side++) {
+            for (int size = 1; size < 8; size++) {
+                Cuboid6 expected = expectedFaceBounds(side, size / 8d);
+                Cuboid6 actual = bounds[size << 4 | side];
+                assertCuboid(expected, actual);
+                populated++;
+            }
+        }
+        for (Cuboid6 bound : bounds) {
+            if (bound != null) {
+                populated--;
+            }
+        }
+        assertEquals(0, populated, "Only the 6 sides by 7 thicknesses may be populated");
+
+        Microblock generated = factory.create(false, 0);
+        assertTrue(generated instanceof FaceMicroblock);
+        assertTrue(generated instanceof TFacePart);
+        for (int side = 0; side < 6; side++) {
+            generated.setShape(3, side);
+            FaceMicroblock face = (FaceMicroblock) generated;
+            assertSame(bounds[3 << 4 | side], face.getBounds());
+            assertEquals(side, face.getSlot());
+            assertEquals(generated.getIMaterial().isSolid(), face.solid(side));
+        }
+    }
+
     @Test
     void registersTheExactOrderedBuiltInMaterialsAndRemaps() throws Exception {
         List<String> expectedNames = new ArrayList<>();
@@ -142,6 +190,34 @@ class DefaultContentFunctionalTest {
         add(names, remaps, block, registeredName, maxMeta, block.getUnlocalizedName());
     }
 
+    private static Cuboid6 expectedFaceBounds(int side, double thickness) {
+        switch (side) {
+            case 0:
+                return new Cuboid6(0, 0, 0, 1, thickness, 1);
+            case 1:
+                return new Cuboid6(0, 1 - thickness, 0, 1, 1, 1);
+            case 2:
+                return new Cuboid6(0, 0, 0, 1, 1, thickness);
+            case 3:
+                return new Cuboid6(0, 0, 1 - thickness, 1, 1, 1);
+            case 4:
+                return new Cuboid6(0, 0, 0, thickness, 1, 1);
+            case 5:
+                return new Cuboid6(1 - thickness, 0, 0, 1, 1, 1);
+            default:
+                throw new AssertionError(side);
+        }
+    }
+
+    private static void assertCuboid(Cuboid6 expected, Cuboid6 actual) {
+        assertEquals(expected.min.x, actual.min.x, 1e-12);
+        assertEquals(expected.min.y, actual.min.y, 1e-12);
+        assertEquals(expected.min.z, actual.min.z, 1e-12);
+        assertEquals(expected.max.x, actual.max.x, 1e-12);
+        assertEquals(expected.max.y, actual.max.y, 1e-12);
+        assertEquals(expected.max.z, actual.max.z, 1e-12);
+    }
+
     private static void add(List<String> names, Map<String, String> remaps, Block block, String registeredName,
             int maxMeta, String oldName) {
         for (int meta = 0; meta <= maxMeta; meta++) {
diff --git a/src/test/java/codechicken/microblock/FaceMicroblockCharacterizationTest.java b/src/test/java/codechicken/microblock/FaceMicroblockCharacterizationTest.java
new file mode 100644
index 0000000..d6f5f96
--- /dev/null
+++ b/src/test/java/codechicken/microblock/FaceMicroblockCharacterizationTest.java
@@ -0,0 +1,179 @@
+package codechicken.microblock;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertSame;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.lang.reflect.Constructor;
+import java.lang.reflect.Field;
+import java.lang.reflect.Method;
+import java.lang.reflect.Modifier;
+import java.util.Arrays;
+import java.util.Set;
+import java.util.TreeSet;
+
+import org.junit.jupiter.api.Test;
+import org.objectweb.asm.Type;
+
+import codechicken.lib.vec.Cuboid6;
+import codechicken.multipart.TFacePart;
+
+class FaceMicroblockCharacterizationTest {
+
+    private static final Set<String> PLACEMENT_FACADE_METHODS = signatures(
+            "customPlacement(Lcodechicken/microblock/MicroblockPlacement;)Lcodechicken/microblock/ExecutablePlacement;",
+            "expand(II)Z",
+            "microClass()Lcodechicken/microblock/FaceMicroClass$;",
+            "opposite(II)I",
+            "placementGrid()Lcodechicken/microblock/FacePlacementGrid$;",
+            "sneakOpposite(II)Z");
+    private static final Set<String> PLACEMENT_COMPANION_METHODS = signatures(
+            "expand(II)Z",
+            "microClass()Lcodechicken/microblock/FaceMicroClass$;",
+            "microClass()Lcodechicken/microblock/MicroblockClass;",
+            "opposite(II)I",
+            "placementGrid()Lcodechicken/microblock/FacePlacementGrid$;",
+            "placementGrid()Lcodechicken/microblock/PlacementGrid;",
+            "sneakOpposite(II)Z");
+    private static final Set<String> CLASS_FACADE_METHODS = signatures(
+            "aBounds()[Lcodechicken/lib/vec/Cuboid6;",
+            "aBounds_$eq([Lcodechicken/lib/vec/Cuboid6;)V",
+            "baseTrait()Ljava/lang/Class;",
+            "baseTraitId()I",
+            "clientTrait()Ljava/lang/Class;",
+            "clientTraitId()I",
+            "create(ZI)Lcodechicken/microblock/Microblock;",
+            "createPart(Ljava/lang/String;Lcodechicken/lib/data/MCDataInput;)Lcodechicken/microblock/Microblock;",
+            "createPart(Ljava/lang/String;Lnet/minecraft/nbt/NBTTagCompound;)Lcodechicken/microblock/Microblock;",
+            "getClassId()I",
+            "getName()Ljava/lang/String;",
+            "getResistanceFactor()F",
+            "itemSlot()I",
+            "placementProperties()Lcodechicken/microblock/FacePlacement$;",
+            "register()V",
+            "register(I)V");
+    private static final Set<String> CLASS_COMPANION_METHODS = signatures(
+            "aBounds()[Lcodechicken/lib/vec/Cuboid6;",
+            "aBounds_$eq([Lcodechicken/lib/vec/Cuboid6;)V",
+            "baseTrait()Ljava/lang/Class;",
+            "clientTrait()Ljava/lang/Class;",
+            "getName()Ljava/lang/String;",
+            "getResistanceFactor()F",
+            "itemSlot()I",
+            "placementProperties()Lcodechicken/microblock/FacePlacement$;",
+            "placementProperties()Lcodechicken/microblock/PlacementProperties;");
+
+    @Test
+    void keepsFacadesCompanionsAndGeneratedTraitSurfaces() throws Exception {
+        assertFacade(FacePlacement.class, true, PLACEMENT_FACADE_METHODS);
+        assertCompanion(FacePlacement$.class, PlacementProperties.class, PLACEMENT_COMPANION_METHODS);
+        assertEquals(1, FacePlacement$.class.getDeclaredFields().length);
+
+        assertFacade(FaceMicroClass.class, false, CLASS_FACADE_METHODS);
+        Constructor<?> constructor = FaceMicroClass.class.getDeclaredConstructor();
+        assertTrue(Modifier.isPublic(constructor.getModifiers()));
+        assertEquals(1, FaceMicroClass.class.getDeclaredConstructors().length);
+        assertCompanion(FaceMicroClass$.class, CommonMicroClass.class, CLASS_COMPANION_METHODS);
+        Field bounds = FaceMicroClass$.class.getDeclaredField("aBounds");
+        assertSame(Cuboid6[].class, bounds.getType());
+        assertTrue(Modifier.isPrivate(bounds.getModifiers()));
+        assertFalse(Modifier.isFinal(bounds.getModifiers()));
+        assertEquals(2, FaceMicroClass$.class.getDeclaredFields().length);
+
+        assertTrait(
+                FaceMicroblock.class,
+                new Class<?>[] { CommonMicroblock.class, TFacePart.class },
+                signatures(
+                        "getBounds()Lcodechicken/lib/vec/Cuboid6;",
+                        "microClass()Lcodechicken/microblock/FaceMicroClass$;",
+                        "solid(I)Z"));
+        assertHelper(
+                "codechicken.microblock.FaceMicroblock$class",
+                signatures(
+                        "$init$(Lcodechicken/microblock/FaceMicroblock;)V",
+                        "getBounds(Lcodechicken/microblock/FaceMicroblock;)Lcodechicken/lib/vec/Cuboid6;",
+                        "microClass(Lcodechicken/microblock/FaceMicroblock;)Lcodechicken/microblock/FaceMicroClass$;",
+                        "solid(Lcodechicken/microblock/FaceMicroblock;I)Z"));
+
+        assertTrait(
+                FaceMicroblockClient.class,
+                new Class<?>[] { CommonMicroblockClient.class },
+                signatures("render(Lcodechicken/lib/vec/Vector3;I)V"));
+        assertHelper(
+                "codechicken.microblock.FaceMicroblockClient$class",
+                signatures(
+                        "$init$(Lcodechicken/microblock/FaceMicroblockClient;)V",
+                        "render(Lcodechicken/microblock/FaceMicroblockClient;Lcodechicken/lib/vec/Vector3;I)V"));
+    }
+
+    @Test
+    void keepsFacePlacementRulesAndGridIdentity() {
+        FacePlacement$ placement = FacePlacement$.MODULE$;
+        assertSame(FacePlacementGrid$.MODULE$, placement.placementGrid());
+        assertSame(FacePlacementGrid$.MODULE$, FacePlacement.placementGrid());
+        assertNull(placement.customPlacement(null));
+        assertNull(FacePlacement.customPlacement(null));
+
+        for (int slot = 0; slot < 6; slot++) {
+            for (int side = 0; side < 6; side++) {
+                boolean sneaking = slot == (side ^ 1);
+                assertEquals(slot ^ 1, placement.opposite(slot, side));
+                assertEquals(slot ^ 1, FacePlacement.opposite(slot, side));
+                assertEquals(sneaking, placement.sneakOpposite(slot, side));
+                assertEquals(sneaking, FacePlacement.sneakOpposite(slot, side));
+                assertEquals(sneaking, placement.expand(slot, side));
+                assertEquals(sneaking, FacePlacement.expand(slot, side));
+            }
+        }
+    }
+
+    private static void assertFacade(Class<?> type, boolean isFinal, Set<String> methods) {
+        assertTrue(Modifier.isPublic(type.getModifiers()));
+        assertEquals(isFinal, Modifier.isFinal(type.getModifiers()));
+        assertSame(Object.class, type.getSuperclass());
+        assertEquals(0, type.getDeclaredFields().length);
+        assertEquals(methods, publicDeclaredMethods(type));
+    }
+
+    private static void assertCompanion(Class<?> type, Class<?> superclass, Set<String> methods) throws Exception {
+        assertTrue(Modifier.isPublic(type.getModifiers()));
+        assertTrue(Modifier.isFinal(type.getModifiers()));
+        assertSame(superclass, type.getSuperclass());
+        assertEquals(methods, publicDeclaredMethods(type));
+        Field module = type.getField("MODULE$");
+        assertSame(type, module.getType());
+        assertTrue(Modifier.isStatic(module.getModifiers()));
+        assertTrue(Modifier.isFinal(module.getModifiers()));
+    }
+
+    private static void assertTrait(Class<?> type, Class<?>[] interfaces, Set<String> methods) {
+        assertTrue(type.isInterface());
+        assertArrayEquals(interfaces, type.getInterfaces());
+        assertEquals(methods, publicDeclaredMethods(type));
+    }
+
+    private static void assertHelper(String name, Set<String> methods) throws Exception {
+        Class<?> type = Class.forName(name, false, FaceMicroblockCharacterizationTest.class.getClassLoader());
+        assertTrue(Modifier.isPublic(type.getModifiers()));
+        assertTrue(Modifier.isAbstract(type.getModifiers()));
+        assertSame(Object.class, type.getSuperclass());
+        assertEquals(methods, publicDeclaredMethods(type));
+    }
+
+    private static Set<String> publicDeclaredMethods(Class<?> type) {
+        Set<String> methods = new TreeSet<>();
+        for (Method method : type.getDeclaredMethods()) {
+            if (Modifier.isPublic(method.getModifiers())) {
+                methods.add(method.getName() + Type.getMethodDescriptor(method));
+            }
+        }
+        return methods;
+    }
+
+    private static Set<String> signatures(String... signatures) {
+        return new TreeSet<>(Arrays.asList(signatures));
+    }
+}