diff --git a/tools/quake3/q3map2/light.c b/tools/quake3/q3map2/light.c
index 5b868bc8..9f06cfd3 100644
--- a/tools/quake3/q3map2/light.c
+++ b/tools/quake3/q3map2/light.c
@@ -1455,6 +1455,8 @@ void TraceGrid( int num )
 	{
 		/* get relative directed strength */
 		d = DotProduct( contributions[ i ].dir, gp->dir );
+		/* we map 1 to gridDirectionality, and 0 to gridAmbientDirectionality */
+		d = gridAmbientDirectionality + d * (gridDirectionality - gridAmbientDirectionality);
 		if( d < 0.0f )
 			d = 0.0f;
 		
@@ -1987,6 +1989,26 @@ int LightMain( int argc, char **argv )
 			gridAmbientScale *= f;
 			i++;
 		}
+
+		else if( !strcmp( argv[ i ], "-griddirectionality" ) )
+		{
+			f = atof( argv[ i + 1 ] );
+			if(f < 0) f = 0;
+			if(f > gridAmbientDirectionality) f = gridAmbientDirectionality;
+			Sys_Printf( "Grid directionality is %f\n", f );
+			gridDirectionality *= f;
+			i++;
+		}
+
+		else if( !strcmp( argv[ i ], "-gridambientdirectionality" ) )
+		{
+			f = atof( argv[ i + 1 ] );
+			if(f > gridDirectionality) f = gridDirectionality
+			if(f > 1) f = 1;
+			Sys_Printf( "Grid ambient directionality is %f\n", f );
+			gridAmbientDirectionality *= f;
+			i++;
+		}
 		
 		else if( !strcmp( argv[ i ], "-gamma" ) )
 		{
diff --git a/tools/quake3/q3map2/q3map2.h b/tools/quake3/q3map2/q3map2.h
index 6deeed24..49710c10 100644
--- a/tools/quake3/q3map2/q3map2.h
+++ b/tools/quake3/q3map2/q3map2.h
@@ -2221,6 +2221,8 @@ Q_EXTERN float				bounceScale Q_ASSIGN( 0.25f );
 /* vortex: gridscale and gridambientscale */
 Q_EXTERN float				gridScale Q_ASSIGN( 1.0f );
 Q_EXTERN float				gridAmbientScale Q_ASSIGN( 1.0f );
+Q_EXTERN float				gridDirectionality Q_ASSIGN( 1.0f );
+Q_EXTERN float				gridAmbientDirectionality Q_ASSIGN( 0.0f );
 
 /* ydnar: lightmap gamma/compensation */
 Q_EXTERN float				lightmapGamma Q_ASSIGN( 1.0f );