The Surface menu contains commands for fitting a surface to your markers.

Selecting Generate Surface sets Prefit to work generating a surface through the marker spline points.

Selecting Regenerate Surface performs a further iteration of the surface fitting algorithm, this will refine the surface net and improve the fit. Modifications to the surface control points may be made prior to selecting Regenerate Surface.

When you select Delete Surface, the surface you have generated is removed from memory permanently.

This function measures the maximum error between the input marker points and the fitted surface.

This function adds further marker points to the stations. These new points are interpolated along the splines, which have been fitted through the original marker data. This may improve the surface fit.

Selecting Control Points presents a dialog in which you may specify the details of the surface which Prefit will fit to the markers.

You may specify the number of rows and columns of controls to be used in the fitted surface. Rows run transversely and columns run longitudinally through the surface, as in Maxsurf. 

In general it is best to use about the same number of control points as you would use to design the hull in Maxsurf. If more controls are used, the more exact the fit through the markers will be, but with a corresponding reduction in surface fairness. The smoothness of the net generated may also deteriorate to the point that it is unworkable.  If too few controls are used, Prefit will not be able to achieve a close fit of the surface to the markers.

Constraints may be imposed on the positions of the surface’s control points; see Section: Control Points for further details.

The maximum number of iterations used in the surface fitting algorithm and the desired error may also be specified.