diff --git a/MatterControlLib/ApplicationView/SceneOperations.cs b/MatterControlLib/ApplicationView/SceneOperations.cs
index 520d1b866..1be4d832f 100644
--- a/MatterControlLib/ApplicationView/SceneOperations.cs
+++ b/MatterControlLib/ApplicationView/SceneOperations.cs
@@ -71,7 +71,7 @@ namespace MatterHackers.MatterControl
 		{
 			return new SceneOperation("AddBase")
 			{
-				OperationType = typeof(IPathObject),
+				OperationType = typeof(IObject3D),
 				TitleResolver = () => "Add Base".Localize(),
 				ResultType = typeof(BaseObject3D),
 				Action = (sceneContext) =>
diff --git a/MatterControlLib/DesignTools/Primitives/BaseObject3D.cs b/MatterControlLib/DesignTools/Primitives/BaseObject3D.cs
index b808b592a..312f04b25 100644
--- a/MatterControlLib/DesignTools/Primitives/BaseObject3D.cs
+++ b/MatterControlLib/DesignTools/Primitives/BaseObject3D.cs
@@ -40,6 +40,7 @@ using MatterHackers.DataConverters2D;
 using MatterHackers.DataConverters3D;
 using MatterHackers.Localizations;
 using MatterHackers.MatterControl.DesignTools.Operations;
+using MatterHackers.PolygonMesh.Csg;
 using MatterHackers.VectorMath;
 using Newtonsoft.Json;
 using Polygon = System.Collections.Generic.List<ClipperLib.IntPoint>;
@@ -125,6 +126,20 @@ namespace MatterHackers.MatterControl.DesignTools
 			get
 			{
 				var vertexSource = (IPathObject)this.Descendants<IObject3D>().FirstOrDefault((i) => i is IPathObject);
+				var meshSource = this.Descendants<IObject3D>().FirstOrDefault((i) => i.Mesh != null);
+				var mesh = meshSource?.Mesh;
+				if (vertexSource?.VertexSource == null
+					&& mesh != null)
+				{
+					// return the vertex source of the bottom of the mesh
+					var aabb = this.GetAxisAlignedBoundingBox();
+					var cutPlane = new Plane(Vector3.UnitZ, new Vector3(0, 0, aabb.MinXYZ.Z + .1));
+					cutPlane = Plane.Transform(cutPlane, this.Matrix.Inverted);
+					var slice = SliceLayer.CreateSlice(mesh, cutPlane);
+					return slice.CreateVertexStorage();
+
+				}
+
 				return vertexSource?.VertexSource;
 			}
 
diff --git a/Submodules/MatterSlice b/Submodules/MatterSlice
index 18f8d4db0..630ef7334 160000
--- a/Submodules/MatterSlice
+++ b/Submodules/MatterSlice
@@ -1 +1 @@
-Subproject commit 18f8d4db0a361138d68845ef24fd22f5804f9347
+Subproject commit 630ef7334038b950c0a9287409c31ab5a70e6f36
diff --git a/Submodules/agg-sharp b/Submodules/agg-sharp
index e56cb7d05..6c49a7095 160000
--- a/Submodules/agg-sharp
+++ b/Submodules/agg-sharp
@@ -1 +1 @@
-Subproject commit e56cb7d0578299174d9fb971e9e731dfb8c29e77
+Subproject commit 6c49a709565589f5e233f81bfc1c1ed60b08361d