# sf_splines

Given a set of control points and spline functions, the sf_splines function returns surface points.

Since: 3.1

## Parameters

• ctrl_pts : A set of control points. See examples below.
• row_spline : The spline function for row points.
• column_spline : The spline function for columns points. Default to row_spline.

## Examples

If you want to make a bezier surface:

ctrl_pts = [
[[0, 0, 20],  [60, 0, -35],   [90, 0, 60],    [200, 0, 5]],
[[0, 50, 30], [100, 60, -25], [120, 50, 120], [200, 50, 5]],
[[0, 100, 0], [60, 120, 35],  [90, 100, 60],  [200, 100, 45]],
[[0, 150, 0], [60, 150, -35], [90, 180, 60],  [200, 150, 45]]
];

thickness = 2;
t_step = 0.05;

bezier = function(points) bezier_curve(t_step, points);

sf_thicken(sf_splines(ctrl_pts, bezier), thickness);

The following figure shows controll points and bazier curves around the surface.

If you want to make a bspline surface:

ctrl_pts = [
[[0, 0, 20],  [60, 0, -35],   [90, 0, 60],    [200, 0, 5]],
[[0, 50, 30], [100, 60, -25], [120, 50, 120], [200, 50, 5]],
[[0, 100, 0], [60, 120, 35],  [90, 100, 60],  [200, 100, 45]],
[[0, 150, 0], [60, 150, -35], [90, 180, 60],  [200, 150, 45]]
];

thickness = 2;
t_step = 0.05;
degrees = 2;

bspline = function(points) bspline_curve(t_step, degrees, points);

sf_thicken(sf_splines(ctrl_pts, bspline), thickness);