Follow this procedure only if you are very early in the design cycle with a model having a minimal number of objects detailed in the Structural Detailing task. Otherwise, follow the procedure described in Swap Hulls on a Detailed Model Using Molded Forms Delay.

Click Select on the vertical toolbar.

Select Molded Forms (Root Level) in the Locate Filter.

Select the existing hull in the model.

On the ribbon, select File Definition .

Select the .SAT or .IGS file that contains the new hull to import.
To show .IGS files in the file browser, you must select IGES files (*.igs) as the file type.

Click Open.

If you are importing a hull from an .IGS file and the file defines only half of the hull, click Mirror surface , Mirror reference curves , or both to import a complete hull.
By default, the two mirror options are disabled. A preview for the hull is updated automatically when you click Mirror surface

Click Finish.
The software displays these curves as part of the plate system surface. The curves are also named, typed, and categorized, allowing you to query for a curve or select the curve and use it as a reference just like any other curve. You can modify the properties of reference curves, such as the name and type. You cannot modify the geometry of a naval architecture reference curve in the software. You must import a new file that contains the modified curve geometry.
The software supports the following ship curves that can be included as naval architecture references curves in the imported file:

Buttock_line  A curve lying on the molded surface of a hull that is the intersection of a longitudinal plane with a hull molded form.

Centerline  A curve lying on the molded surface of a hull that is the intersection of the longitudinal center plane with the hull molded form.

Flat_of_Bottom  The boundary curve of the bottom planar surface at the hull molded form base.

Flat_of_Side  The boundary curve of the side planar surface at the outermost port or starboard side of the hull molded form.

Intersection_Line  A curve that is the intersection of two surfaces found on, or within, a molded form.

Station_Line  A curve lying on the hull molded surface that is the intersection of a transverse plane with a hull molded form.

Waterline  A curve lying on the hull molded surface that is the intersection of the water plane with the hull molded form.

Bounding_Line  Any bounding curve of a ship surface.

Unspecified  A curve whose relation to naval architecture is not known or not recorded.
The software recognizes the following types of naval architecture reference curves:

Knuckle Curves (KNU)  A 3D curve on the hull surface that exhibits tangent discontinuity (knuckle constraint) of more than one degree anywhere along its curve geometry. Multiple knuckle curves can occur and are given unique names. Knuckle reference curves support rules that determine the production method (bend, split, or ignore) governing their treatment and processing in the model.

Tangent Curves (TAN)  A 3D curve on the hull surface that exhibits tangency constraint when intersected by orthogonal curves (section, waterlines, and buttocks). Multiple tangent curves can occur and are given unique names.

Stem and Stern Profiles Curves (STM PROF and STR PROF)  The profile curves that define the outline of the hull at the Y=0 position. It is usually split into two individual curves, the Stem and Stern Profile. These two curves meet at amidships at Z=0. These curves are unique to single hulls.

Stem and Stern Half Siding Curves (HS STM and HS STR)  The stem and stern halfsiding curve is a 3D curve that defines the points at which waterline endings knuckle in to the centerline of the hull (stem and stern profile). The resulting surface bounded by the halfsiding curve is a flat surface. These curves are unique to single hulls.

Stem and Stern Tangent Curves (STM TAN, STR TAN)  The stem and stern tangent curve is a 3D curve that defines the points at which waterline endings are tangential into a circular or elliptical waterline ending. The resulting surface bounded by the tangent curve is a circular or elliptical part cone. These curves are unique in single hulls.