diff --git a/panda/src/gobj/geomVertexReader.I b/panda/src/gobj/geomVertexReader.I
index e78f131bcc..3ef683ca32 100644
--- a/panda/src/gobj/geomVertexReader.I
+++ b/panda/src/gobj/geomVertexReader.I
@@ -17,6 +17,21 @@
 ////////////////////////////////////////////////////////////////////
 
 
+////////////////////////////////////////////////////////////////////
+//     Function: GeomVertexReader::Default Constructor
+//       Access: Published
+//  Description: Constructs an invalid GeomVertexReader.  You must use
+//               the assignment operator to assign a valid
+//               GeomVertexReader to this object before you can use
+//               it.
+////////////////////////////////////////////////////////////////////
+INLINE GeomVertexReader::
+GeomVertexReader() :
+  _vertex_data(NULL)
+{
+  initialize();
+}
+
 ////////////////////////////////////////////////////////////////////
 //     Function: GeomVertexReader::Constructor
 //       Access: Published
diff --git a/panda/src/gobj/geomVertexReader.h b/panda/src/gobj/geomVertexReader.h
index 828affcbcc..fed1d58879 100644
--- a/panda/src/gobj/geomVertexReader.h
+++ b/panda/src/gobj/geomVertexReader.h
@@ -59,6 +59,7 @@
 ////////////////////////////////////////////////////////////////////
 class EXPCL_PANDA GeomVertexReader : public GeomEnums {
 PUBLISHED:
+  INLINE GeomVertexReader();
   INLINE GeomVertexReader(const GeomVertexData *vertex_data);
   INLINE GeomVertexReader(const GeomVertexData *vertex_data,
                           const string &name);
diff --git a/panda/src/gobj/geomVertexRewriter.I b/panda/src/gobj/geomVertexRewriter.I
index 35761da0ab..ec5a415e4a 100644
--- a/panda/src/gobj/geomVertexRewriter.I
+++ b/panda/src/gobj/geomVertexRewriter.I
@@ -17,6 +17,18 @@
 ////////////////////////////////////////////////////////////////////
 
 
+////////////////////////////////////////////////////////////////////
+//     Function: GeomVertexRewriter::Default Constructor
+//       Access: Published
+//  Description: Constructs an invalid GeomVertexRewriter.  You must use
+//               the assignment operator to assign a valid
+//               GeomVertexRewriter to this object before you can use
+//               it.
+////////////////////////////////////////////////////////////////////
+INLINE GeomVertexRewriter::
+GeomVertexRewriter() {
+}
+
 ////////////////////////////////////////////////////////////////////
 //     Function: GeomVertexRewriter::Constructor
 //       Access: Published
diff --git a/panda/src/gobj/geomVertexRewriter.h b/panda/src/gobj/geomVertexRewriter.h
index b0faf78b89..ae8f505b6a 100644
--- a/panda/src/gobj/geomVertexRewriter.h
+++ b/panda/src/gobj/geomVertexRewriter.h
@@ -42,6 +42,7 @@
 ////////////////////////////////////////////////////////////////////
 class EXPCL_PANDA GeomVertexRewriter : public GeomVertexWriter, public GeomVertexReader {
 PUBLISHED:
+  INLINE GeomVertexRewriter();
   INLINE GeomVertexRewriter(GeomVertexData *vertex_data);
   INLINE GeomVertexRewriter(GeomVertexData *vertex_data,
                             const string &name);
diff --git a/panda/src/gobj/geomVertexWriter.I b/panda/src/gobj/geomVertexWriter.I
index 470a4b430b..57be772cc8 100644
--- a/panda/src/gobj/geomVertexWriter.I
+++ b/panda/src/gobj/geomVertexWriter.I
@@ -17,6 +17,21 @@
 ////////////////////////////////////////////////////////////////////
 
 
+////////////////////////////////////////////////////////////////////
+//     Function: GeomVertexWriter::Default Constructor
+//       Access: Published
+//  Description: Constructs an invalid GeomVertexWriter.  You must use
+//               the assignment operator to assign a valid
+//               GeomVertexWriter to this object before you can use
+//               it.
+////////////////////////////////////////////////////////////////////
+INLINE GeomVertexWriter::
+GeomVertexWriter() :
+  _vertex_data(NULL)
+{
+  initialize();
+}
+
 ////////////////////////////////////////////////////////////////////
 //     Function: GeomVertexWriter::Constructor
 //       Access: Published
diff --git a/panda/src/gobj/geomVertexWriter.h b/panda/src/gobj/geomVertexWriter.h
index 14d465902b..14c7574bf5 100644
--- a/panda/src/gobj/geomVertexWriter.h
+++ b/panda/src/gobj/geomVertexWriter.h
@@ -72,6 +72,7 @@
 ////////////////////////////////////////////////////////////////////
 class EXPCL_PANDA GeomVertexWriter : public GeomEnums {
 PUBLISHED:
+  INLINE GeomVertexWriter();
   INLINE GeomVertexWriter(GeomVertexData *vertex_data);
   INLINE GeomVertexWriter(GeomVertexData *vertex_data,
                           const string &name);