diff --git a/pcdet/models/backbones_2d/map_to_bev/__init__.py b/pcdet/models/backbones_2d/map_to_bev/__init__.py
new file mode 100644
index 0000000..e7724d1
--- /dev/null
+++ b/pcdet/models/backbones_2d/map_to_bev/__init__.py
@@ -0,0 +1,10 @@
+from .height_compression import HeightCompression
+from .pointpillar_scatter import PointPillarScatter, PointPillarScatter3d
+from .conv2d_collapse import Conv2DCollapse
+
+__all__ = {
+    'HeightCompression': HeightCompression,
+    'PointPillarScatter': PointPillarScatter,
+    'Conv2DCollapse': Conv2DCollapse,
+    'PointPillarScatter3d': PointPillarScatter3d,
+}