Create a curved line by marking specific points of curvature using the spline from the sketch toolbar. This creates a polynomial curve, or curve with multiple points. With splines, you can construct complex curves and create organic shapes. Splines have two different types called Fit Point Splines and Control Point Splines. Follow this guide to learn about the two types of splines.

Fit Point Splines

To create a curve by marking the specific location of each point through which the curve should pass, use the Fit Point Spline. Fit Point Splines give you more flexibility to set the spline path. The challenge is controlling the whole curve since any change to a point impacts other parts of the spline more easily.

To create Fit Point Splines, follow these steps:

1. Go to Sketch > Spline, then choose Fit.
2. Draw a curve segment, then lift the Pencil.
3. Draw more connecting curve segments.
4. To move the curve points, select and drag them directly.
5. To adjust the curvature at a point, select it and drag the handles.
   
   
6. To add points to the spline, select the curve and long-tap it.
7. To remove a point, select it and then tap Delete.
8. To break or join splines at any point, select it and then tap the Break/Join toggle.
   
   

Control Point Splines

Use Control Point Splines to draw and shape a curve indirectly. As you draw each section, a polyline appears to guide the curve. Each point that you mark is a vertex of a polyline (invisible) that you can tap and move to adjust the shape of the curve. This approach gives you less direct manipulation, but more control over the full curve’s smoothness.

To create Control Point Splines, follow these steps:

1. Go to Sketch > Spline, then choose Control.
2. Draw connecting lines. This creates a polyline that guides the shape of the curve.
   
3. To adjust the curve, drag the control points, not the curve itself.
   
   
4. To add a control point, select the curve and long-tap it.
5. To remove a point, select it and tap Delete.
6. To break or join splines at any point, select it and then tap the Break/Join toggle.
   
   
7. To connect straight lines with a tangent curve, make sure the spline’s control polyline is in line with the neighboring lines. This will create the curve tangent at these points.