1. Start by drawing the midship section of a ship hull form using an Intellicurve (Create -> IntelliCurve). Use sixteen points, one for the keel, five for the flat of botton, four for the bilge radius, five for the flat of side and one for the deck line. (The section should ideally be drawn in the y-z plane, but this images show this can be rectified later).

2. Control the shape of the bilge radius to form a curve by applying a curve or blend constraint. Select the four bilge radius control points...

... in the attribute panel, apply the curve constraint by pressing the button.

The two internal points from the bilge group are hidden and are now controlled by the constraint relationship.

3. Control the shape of the flat of bottom by applying a straight constraint. Select all the points from the keel to the first point of the bilge radius group...

...in the attribute panel, apply the straight constraint by pressing the button.

The control points on the flat of bottom are hidden and are now controlled by the straight constraint relationship. The previously applied curve constraint recognises the proximaty of the straight constraint and changes the control points on the bilge radius so that a tangential relationship is formed as the curve transitions from the flat of bottom to the bilge radius.

4. Repeat the process on the flat of side by selecting all the points from the last point on the bilge radius to the deck point...

...in the attribute panel, apply the straight constraint by pressing the button.

The ship midship section shape is now formed with a flat of bottom, side and bilge radius. The curve has sixteen points but only 4 are visible and are the only one needed to control the shape of the hull section.

5. Modify the point locations in the attribute panel so that the hull has a breadth of 20.0m, depth of 12.5m with a bilge radius of 2.0.

The shape of the hull is now accuratly formed.

6. The midship section now needs to be placed in the centre of the hull. A plane constraint can be applied to the section forcing points to lie on a 2D plane. The plane can then be moved tranlating all the control points on the curve. In the attributes panel, press the button. "Plane <undefined>" now appears in the constraint line up. Select this line and the Plane Constraint details will appear. Constrain the curve so that it can only be modified in Y-Z by pressing the 'X' radiobutton. Move the curve to the centre of the vessel by changing the plane to "X = 50.000". Now zoom all.