Understanding Bézier curves

While lines on computers are easy to store with a start and end point, curves require more information. In FreeSewing — as in SVG and countless of other computer applications — curves are stored as Bézier curves, named after French engineer Pierre Bézier who popularized their use back in the 1960s.

In FreeSewing, we use so-called cubic Bézier curves which have:

• A start point
• A first control point that’s linked to the start point
• A second control point that’s linked to the end point
• An end point

Bézier curves and their handles or control points are surprisingly intuitive. The following illustration does a great job at explaining how they are constructed:

You don’t need to understand the mathematics behind Bézier Curves. As long as you intuitively get how the control points influence the curve, you’re good to go.