diff --git a/pandatool/src/lwo/lwoDiscontinuousVertexMap.h b/pandatool/src/lwo/lwoDiscontinuousVertexMap.h
index 9d62a63b7d..009e8d7da7 100644
--- a/pandatool/src/lwo/lwoDiscontinuousVertexMap.h
+++ b/pandatool/src/lwo/lwoDiscontinuousVertexMap.h
@@ -20,6 +20,7 @@
 #include "lwoChunk.h"
 
 #include "pta_float.h"
+#include "pmap.h"
 
 ////////////////////////////////////////////////////////////////////
 //       Class : LwoDiscontinuousVertexMap