diff --git a/vcg/space/index/grid_util.h b/vcg/space/index/grid_util.h
index ff431010..ce307747 100644
--- a/vcg/space/index/grid_util.h
+++ b/vcg/space/index/grid_util.h
@@ -158,17 +158,27 @@ public:
 	 * @return b is the corresponding box in <ScalarType> coordinates
 	 */
 	inline void IPiToBox(const Point3i & pi, Box3x & b ) const
-	{
-		CoordType p;
+	{
+		CoordType p;
 		p[0] = ((ScalarType)pi[0])*voxel[0];
 		p[1] = ((ScalarType)pi[1])*voxel[1];
 		p[2] = ((ScalarType)pi[2])*voxel[2];
-		p += bbox.min;
-		b.min = p;
-		b.max = (p + voxel);
+		p += bbox.min;
+		b.min = p;
+		b.max = (p + voxel);
 	}
 
-	// Same of above but for the case that you just want to transform 
+	/* Given a cell index return the center of the cell itself
+	 * @param integer coordinates pi of the cell
+	 * @return b is the corresponding box in <ScalarType> coordinates
+	 */inline void IPiToBoxCenter(const Point3i & pi, CoordType & c ) const
+	{
+		CoordType p;
+		IPiToPf(pi,p);
+		c = p + voxel/ScalarType(2.0);
+	}
+
+	// Same of IPiToPf but for the case that you just want to transform 
 	// from a space to the other.
 	inline void IPfToPf(const CoordType & pi, CoordType &p ) const
 	{