It relates to digitizing and CAD design.

Bézier curves are used a lot in computer graphics, often to produce smooth curves, and yet they are a very simple tool. see link

Thanks girls. I was looking at different digitizing programmes and it was commented that it wasn't present in Embird. Do I presume its in PE design? Just curious if others knew what it was/is?

Embird has a two-point feature that gives a really nice curve (see pic 4). You place a first and second point - see pic 1 - and as soon as you place the third a nice arc/curve is formed - pic 2. However, it does not readjust between a first curve and the following one, but leaves a sharpish corner - pic 3. So it might not be a real Bézier curve.
I don't have PE design, so I don't know about that one.

Looks like you got our answer as to what it is... FTCU also has this feature. However, my Janome Digitizer does not...it does, however allow you to make a curved line by using the right click on the mouse.

PE design 10 has a curve a bit like Mops is showing, I haven;t used it, you can do a circle select the stitches and change the shape also..wendy