diff --git a/src/deh_tables.c b/src/deh_tables.c
index 6344d3ceb..5b2b81153 100644
--- a/src/deh_tables.c
+++ b/src/deh_tables.c
@@ -5688,6 +5688,7 @@ const char *const MSF_LIST[] = {
 	"RIPPLE_CEILING",
 	"INVERTENCORE",
 	"FLATLIGHTING",
+	"DIRECTIONLIGHTING",
 	NULL
 };
 
diff --git a/src/p_setup.c b/src/p_setup.c
index 2ebc3a6d7..5e3f5a54b 100644
--- a/src/p_setup.c
+++ b/src/p_setup.c
@@ -1714,6 +1714,8 @@ static void ParseTextmapSectorParameter(UINT32 i, const char *param, const char
 		sectors[i].flags |= MSF_INVERTENCORE;
 	else if (fastcmp(param, "flatlighting") && fastcmp("true", val))
 		sectors[i].flags |= MSF_FLATLIGHTING;
+	else if (fastcmp(param, "forcedirectionallighting") && fastcmp("true", val))
+		sectors[i].flags |= MSF_DIRECTIONLIGHTING;
 	else if (fastcmp(param, "nostepup") && fastcmp("true", val))
 		sectors[i].specialflags |= SSF_NOSTEPUP;
 	else if (fastcmp(param, "doublestepup") && fastcmp("true", val))
@@ -3369,6 +3371,12 @@ void P_UpdateSegLightOffset(seg_t *li)
 
 boolean P_SectorUsesDirectionalLighting(const sector_t *sector)
 {
+	// explicitly turned on
+	if (sector->flags & MSF_DIRECTIONLIGHTING)
+	{
+		return true;
+	}
+
 	// explicitly turned off
 	if (sector->flags & MSF_FLATLIGHTING)
 	{
diff --git a/src/r_defs.h b/src/r_defs.h
index 82f98bfa7..cf8801f75 100644
--- a/src/r_defs.h
+++ b/src/r_defs.h
@@ -352,6 +352,8 @@ typedef enum
 	MSF_INVERTENCORE            =  1<<12,
 	// turn off directional lighting
 	MSF_FLATLIGHTING            =  1<<13,
+	// force it on (even if it was disabled)
+	MSF_DIRECTIONLIGHTING       =  1<<14,
 } sectorflags_t;
 
 typedef enum