Now that you have set the flexibility of the splines to be used, you can fit the splines through the markers by choosing Section Splines  from the Display menu. This will calculate all the splines and display the spline, which has been fitted through the current section. Selecting Edge Splines from the Display menu will calculate and display the splines, which are fitted through the sheerline and keel.

Once Prefit has calculated the spline, it will be drawn as a solid line through, or very close to, the marker points.

If you wish you can modify any spline control point. To do this, select Spline Controls from the Display menu. Spline Controls shows the control points for the spline as generated by Prefit. You can drag the control points with the mouse to modify the fit of the spline to the marker points. The movement may be constrained to the vertical or horizontal direction by pressing the shift key while dragging the control point.

Remember that if you are only showing one section at a time, you can change the current section by clicking on the desired station marker in the inset box at the top right of the Body Plan window.

When modifying the bow and stern definitions be sure to refer to the Plan and Profile windows to check for fairness as well as in the Body Plan window.

Profile and Plan views showing control points with constant longitudinal position for intermediate stations and a completed definition of the bow and stern.

The splines generated through the top and bottom edges of the surface (normally keel and sheerline) may be manipulated in a similar manner.