diff --git a/src/ifcopenshell-python/ifcopenshell/api/material/assign_material.py b/src/ifcopenshell-python/ifcopenshell/api/material/assign_material.py
index 3a4f751e45..2b5a498061 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/material/assign_material.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/material/assign_material.py
@@ -1,4 +1,5 @@
 import ifcopenshell
+import ifcopenshell.api
 import ifcopenshell.util.element
 
 
@@ -10,6 +11,9 @@ class Usecase:
             self.settings[key] = value
 
     def execute(self):
+        material = ifcopenshell.util.element.get_material(self.settings["product"])
+        if material:
+            ifcopenshell.api.run("material.unassign_material", self.file, product=self.settings["product"])
         if self.settings["type"] == "IfcMaterial":
             self.assign_ifc_material()
         elif self.settings["type"] == "IfcMaterialConstituentSet":
diff --git a/src/ifcopenshell-python/ifcopenshell/api/material/unassign_material.py b/src/ifcopenshell-python/ifcopenshell/api/material/unassign_material.py
index 8a6fad3b53..5c16e48a90 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/material/unassign_material.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/material/unassign_material.py
@@ -9,6 +9,15 @@ class Usecase:
             self.settings[key] = value
 
     def execute(self):
-        for association in self.settings["product"].HasAssociations:
-            if association.is_a("IfcRelAssociatesMaterial"):
-                self.file.remove(association)
+        for rel in self.settings["product"].HasAssociations:
+            if rel.is_a("IfcRelAssociatesMaterial"):
+                if rel.RelatingMaterial.is_a("IfcMaterialLayerSetUsage") or rel.RelatingMaterial.is_a(
+                    "IfcMaterialProfileSetUsage"
+                ):
+                    self.file.remove(rel.RelatingMaterial)
+                if len(rel.RelatedObjects) == 1:
+                    self.file.remove(rel)
+                    continue
+                related_objects = set(rel.RelatedObjects)
+                related_objects.remove(self.settings["product"])
+                rel.RelatedObjects = list(related_object)
diff --git a/src/ifcopenshell-python/ifcopenshell/api/type/assign_type.py b/src/ifcopenshell-python/ifcopenshell/api/type/assign_type.py
index 38f4c84449..d11fb8f3ae 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/type/assign_type.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/type/assign_type.py
@@ -1,5 +1,6 @@
 import ifcopenshell
 import ifcopenshell.api
+import ifcopenshell.util.element
 
 
 class Usecase:
@@ -54,6 +55,7 @@ class Usecase:
             )
 
         self.map_representations()
+        self.map_material_usages()
 
     def map_representations(self):
         if not self.settings["relating_type"].RepresentationMaps:
@@ -79,3 +81,20 @@ class Usecase:
                 self.file,
                 **{"product": self.settings["related_object"], "representation": mapped_representation}
             )
+
+    def map_material_usages(self):
+        type_material = ifcopenshell.util.element.get_material(self.settings["relating_type"])
+        if type_material.is_a("IfcMaterialLayerSet"):
+            ifcopenshell.api.run(
+                "material.assign_material",
+                self.file,
+                product=self.settings["related_object"],
+                type="IfcMaterialLayerSetUsage",
+            )
+        elif type_material.is_a("IfcMaterialProfileSet"):
+            ifcopenshell.api.run(
+                "material.assign_material",
+                self.file,
+                product=self.settings["related_object"],
+                type="IfcMaterialProfileSetUsage",
+            )