diff --git a/postgis/lwgeom_box.c b/postgis/lwgeom_box.c
index 2babe68be..4bb36a839 100644
--- a/postgis/lwgeom_box.c
+++ b/postgis/lwgeom_box.c
@@ -1,3 +1,16 @@
+/**********************************************************************
+ * $Id$
+ *
+ * PostGIS - Spatial Types for PostgreSQL
+ * http://postgis.refractions.net
+ * Copyright 2001-2009 Refractions Research Inc.
+ * Copyright 2009 Mark Cave-Ayland <mark.cave-ayland@siriusit.co.uk>
+ *
+ * This is free software; you can redistribute and/or modify it under
+ * the terms of the GNU General Public Licence. See the COPYING file.
+ *
+ **********************************************************************/
+
 #include "postgres.h"
 #include "utils/geo_decls.h"
 
@@ -5,38 +18,38 @@
 #include "liblwgeom.h"
 
 
-void box_to_box2df(BOX *box, BOX2DFLOAT4 *out);
+void box_to_box3d(BOX *box, BOX3D *out);
+void box3d_to_box_p(BOX3D *box, BOX *out);
 
 
-
-/* convert postgresql BOX to BOX2D */
+/* convert postgresql BOX to BOX3D */
 void
-box_to_box2df(BOX *box, BOX2DFLOAT4 *out)
+box_to_box3d(BOX *box, BOX3D *out)
 {
 #if PARANOIA_LEVEL > 0
 	if (box == NULL) return;
 #endif
 
-	out->xmin = nextDown_f(box->low.x);
-	out->ymin = nextDown_f(box->low.y);
+	out->xmin = box->low.x;
+	out->ymin = box->low.y;
 
-	out->xmax = nextUp_f(box->high.x);
-	out->ymax = nextUp_f(box->high.x);
+	out->xmax = box->high.x;
+	out->ymax = box->high.y;
 
 }
 
-/* convert BOX2D to postgresql BOX */
+/* convert BOX3D to postgresql BOX */
 void
-box2df_to_box_p(BOX2DFLOAT4 *box, BOX *out)
+box3d_to_box_p(BOX3D *box, BOX *out)
 {
 #if PARANOIA_LEVEL > 0
 	if (box == NULL) return;
 #endif
 
-	out->low.x = nextDown_d(box->xmin);
-	out->low.y = nextDown_d(box->ymin);
+	out->low.x = box->xmin;
+	out->low.y = box->ymin;
 
-	out->high.x = nextUp_d(box->xmax);
-	out->high.y = nextUp_d(box->ymax);
+	out->high.x = box->xmax;
+	out->high.y = box->ymax;
 }
 
diff --git a/postgis/lwgeom_box3d.c b/postgis/lwgeom_box3d.c
index 813fcd86f..4d1d1df79 100644
--- a/postgis/lwgeom_box3d.c
+++ b/postgis/lwgeom_box3d.c
@@ -150,10 +150,9 @@ PG_FUNCTION_INFO_V1(BOX3D_to_BOX);
 Datum BOX3D_to_BOX(PG_FUNCTION_ARGS)
 {
 	BOX3D *in = (BOX3D *)PG_GETARG_POINTER(0);
-	BOX2DFLOAT4 *box2d = box3d_to_box2df(in);
 	BOX *box = palloc(sizeof(BOX));
 
-	box2df_to_box_p(box2d, box);
+	box3d_to_box_p(in, box);
 	PG_RETURN_POINTER(box);
 }
 
diff --git a/postgis/lwgeom_functions_basic.c b/postgis/lwgeom_functions_basic.c
index 98d31a00f..6892cb517 100644
--- a/postgis/lwgeom_functions_basic.c
+++ b/postgis/lwgeom_functions_basic.c
@@ -2400,17 +2400,18 @@ Datum LWGEOM_expand(PG_FUNCTION_ARGS)
 PG_FUNCTION_INFO_V1(LWGEOM_to_BOX);
 Datum LWGEOM_to_BOX(PG_FUNCTION_ARGS)
 {
-	PG_LWGEOM *lwgeom = (PG_LWGEOM *)PG_DETOAST_DATUM(PG_GETARG_DATUM(0));
-	BOX2DFLOAT4 box2d;
+	PG_LWGEOM *pg_lwgeom = (PG_LWGEOM *)PG_DETOAST_DATUM(PG_GETARG_DATUM(0));
+	BOX3D *box3d;
 	BOX *result = (BOX *)lwalloc(sizeof(BOX));
+	LWGEOM *lwgeom = lwgeom_deserialize(SERIALIZED_FORM(pg_lwgeom));
 
-	if ( ! getbox2d_p(SERIALIZED_FORM(lwgeom), &box2d) )
-	{
-		PG_RETURN_NULL(); /* must be the empty geometry */
-	}
-	box2df_to_box_p(&box2d, result);
+	/* Calculate the BOX3D of the geometry */
+	box3d = lwgeom_compute_box3d(lwgeom);
+	box3d_to_box_p(box3d, result);
+	lwfree(box3d);
+	lwfree(lwgeom);
 
-	PG_FREE_IF_COPY(lwgeom, 0);
+	PG_FREE_IF_COPY(pg_lwgeom, 0);
 
 	PG_RETURN_POINTER(result);
 }
diff --git a/postgis/lwgeom_pg.h b/postgis/lwgeom_pg.h
index d9be4e051..08a8c3145 100644
--- a/postgis/lwgeom_pg.h
+++ b/postgis/lwgeom_pg.h
@@ -82,8 +82,8 @@ extern Oid getGeometryOID(void);
 
 /* PG-dependant */
 /* BOX is postgresql standard type */
-extern void box_to_box2df_p(BOX *box, BOX2DFLOAT4 *out);  
-extern void box2df_to_box_p(BOX2DFLOAT4 *box, BOX *out);
+extern void box_to_box3d_p(BOX *box, BOX3D *out);  
+extern void box3d_to_box_p(BOX3D *box, BOX *out);
 
 /* PG-exposed */
 Datum BOX2D_same(PG_FUNCTION_ARGS);