diff --git a/source/duke3d/src/gamedef.cpp b/source/duke3d/src/gamedef.cpp
index d72bc485a..0618f4f05 100644
--- a/source/duke3d/src/gamedef.cpp
+++ b/source/duke3d/src/gamedef.cpp
@@ -5947,6 +5947,9 @@ static void C_AddDefaultDefinitions(void)
 
     static tokenmap_t predefined[] =
     {
+        { "CLIPMASK0",         CLIPMASK0 },
+        { "CLIPMASK1",         CLIPMASK1 },
+
         { "GAMEARRAY_BOOLEAN", GAMEARRAY_BITMAP },
         { "GAMEARRAY_INT16",   GAMEARRAY_INT16 },
         { "GAMEARRAY_INT8",    GAMEARRAY_INT8 },
diff --git a/source/duke3d/src/gamevars.cpp b/source/duke3d/src/gamevars.cpp
index c54a85558..57733c88f 100644
--- a/source/duke3d/src/gamevars.cpp
+++ b/source/duke3d/src/gamevars.cpp
@@ -1263,8 +1263,6 @@ static void Gv_AddSystemVars(void)
 #else
     Gv_NewVar("ANGRANGE",              18,                                      GAMEVAR_SYSTEM | GAMEVAR_PERPLAYER);
     Gv_NewVar("AUTOAIMANGLE",          0,                                       GAMEVAR_SYSTEM | GAMEVAR_PERPLAYER);
-    Gv_NewVar("CLIPMASK0",             CLIPMASK0,                               GAMEVAR_SYSTEM | GAMEVAR_READONLY);
-    Gv_NewVar("CLIPMASK1",             CLIPMASK1,                               GAMEVAR_SYSTEM | GAMEVAR_READONLY);
     Gv_NewVar("COOP",                  (intptr_t)&ud.coop,                      GAMEVAR_SYSTEM | GAMEVAR_INT32PTR);
     Gv_NewVar("FFIRE",                 (intptr_t)&ud.ffire,                     GAMEVAR_SYSTEM | GAMEVAR_INT32PTR);
     Gv_NewVar("GRENADE_LIFETIME",      NAM_GRENADE_LIFETIME,                    GAMEVAR_SYSTEM | GAMEVAR_PERPLAYER);