diff --git a/panda/src/collide/collisionDSSolid.h b/panda/src/collide/collisionDSSolid.h
index 83a7405e5a..8ad3c432e1 100755
--- a/panda/src/collide/collisionDSSolid.h
+++ b/panda/src/collide/collisionDSSolid.h
@@ -21,7 +21,7 @@
 #define COLLISIONDSSOLID_H
 
 #include "pandabase.h"
-
+#include "plane.h"
 #include "collisionSolid.h"
 
 ////////////////////////////////////////////////////////////////////