diff --git a/docs/lib3x-sf_splines.md b/docs/lib3x-sf_splines.md
index 74e69ee7..ff3f12b7 100644
--- a/docs/lib3x-sf_splines.md
+++ b/docs/lib3x-sf_splines.md
@@ -15,8 +15,8 @@ Given a set of control points and spline functions, the `sf_splines` function re
 If you want to make a bezier surface:
 
 	use <bezier_curve.scad>;
-	use <function_grapher.scad>;
 	use <surface/sf_splines.scad>;
+	use <surface/sf_thicken.scad>;
 
 	ctrl_pts = [
 		[[0, 0, 20],  [60, 0, -35],   [90, 0, 60],    [200, 0, 5]],
@@ -30,7 +30,7 @@ If you want to make a bezier surface:
 
 	bezier = function(points) bezier_curve(t_step, points);
 
-	function_grapher(sf_splines(ctrl_pts, bezier), thickness);
+	sf_thicken(sf_splines(ctrl_pts, bezier), thickness);
 
 ![sf_splines](images/lib3x-sf_splines-1.JPG)
 
@@ -41,7 +41,7 @@ The following figure shows controll points and bazier curves around the surface.
 If you want to make a bspline surface:
 
 	use <bspline_curve.scad>;
-	use <function_grapher.scad>;
+	use <surface/sf_thicken.scad>;
 	use <surface/sf_splines.scad>;
 
 	ctrl_pts = [
@@ -57,6 +57,6 @@ If you want to make a bspline surface:
 
 	bspline = function(points) bspline_curve(t_step, degrees, points);
 
-	function_grapher(sf_splines(ctrl_pts, bspline), thickness);
+	sf_thicken(sf_splines(ctrl_pts, bspline), thickness);
 
 ![sf_splines](images/lib3x-sf_splines-3.JPG)
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