diff --git a/masque/shapes/poly_collection.py b/masque/shapes/poly_collection.py
index 6c23da7..0b5543f 100644
--- a/masque/shapes/poly_collection.py
+++ b/masque/shapes/poly_collection.py
@@ -119,6 +119,22 @@ class PolyCollection(Shape):
         if numpy.any(offset):
             self.translate(offset)
 
+    @classmethod
+    def _from_raw(
+            cls,
+            *,
+            vertex_lists: NDArray[numpy.float64],
+            vertex_offsets: NDArray[numpy.integer[Any]],
+            annotations: annotations_t = None,
+            repetition: Repetition | None = None,
+            ) -> Self:
+        new = cls.__new__(cls)
+        new._vertex_lists = vertex_lists
+        new._vertex_offsets = vertex_offsets
+        new._repetition = repetition
+        new._annotations = annotations
+        return new
+
     def __deepcopy__(self, memo: dict | None = None) -> Self:
         memo = {} if memo is None else memo
         new = copy.copy(self)
diff --git a/masque/shapes/polygon.py b/masque/shapes/polygon.py
index a743de2..42c2f78 100644
--- a/masque/shapes/polygon.py
+++ b/masque/shapes/polygon.py
@@ -131,6 +131,20 @@ class Polygon(Shape):
         if numpy.any(offset):
             self.translate(offset)
 
+    @classmethod
+    def _from_raw(
+            cls,
+            *,
+            vertices: NDArray[numpy.float64],
+            annotations: annotations_t = None,
+            repetition: Repetition | None = None,
+            ) -> Self:
+        new = cls.__new__(cls)
+        new._vertices = vertices
+        new._repetition = repetition
+        new._annotations = annotations
+        return new
+
     def __deepcopy__(self, memo: dict | None = None) -> 'Polygon':
         memo = {} if memo is None else memo
         new = copy.copy(self)