Splines are curved sketches defined by control or fit points, you can use them to create organic shapes. The app supports two spline representations.
Fit point splines: The spline goes through each fit point smoothly
Control point splines: Every created point is a vertex of a polyline (invisible), the app creates a smoothed version of it automatically
You can choose between the two types of splines after tapping on the Spline tool in the Sketch Menu
Drawing a fit point spline
1. Start drawing a line with the Apple Pencil
2. Press with the pencil to place a control point
3. Release the pressure on the pencil (without lifting the Pencil from the screen)
4. Keep drawing, and adding control points.
5. Release the pencil from the screen. Your spline is ready
6. Move or delete the control points to adjust the spline.
Adding and removing spline points (fit-point spline)
You can add points to a fit-point spline, by pushing down your Pencil on the spline, just like you would during the initial process of creating it.
You can delete a point by selecting it and tapping on Delete.
With every press, you will create another control point or fit point. You can modify the position of these control points later.
If the starting point and the endpoint of the spline are connected, you'll create a closed spline.