Example of a smoothed surface:

In the CAD module click on " new file "

For this example, use the dimension parameters of the default blank.

Create a new window and arrange the screen as on the following view by attributing the " perspective " view to the smallest window. Activate the " realistic rendering " on the " XY " view.

Draw four profiles similar to those in the example. Take care, each profile must stop at about the middle of the drawing area and it is imperative for them to stop at the same " X " coordinate to be able to create perfect symmetry.

You can, as in the example, draw an axis in a different colour and plane to have a marker.

The shape of the profiles is of no importance for this example, you can use Béziers curves, polylines or arcs if you wish.

Once the profiles are drawn, delete the marker axis if you have created one and select all of the four profiles.

Make an " any axis " symmetry with duplication designating as symmetry axis the vertical axis of the straight ends of the profiles

The profiles thus created are in two parts. So it is imperative to join them to create four whole entities.

Select the top profile (or the bottom if you prefer!) composed of two curves.

Join them using the " join " function of the " edit " menu.

Repeat this operation on the other three profiles.

Once the joins are made, you will make a rotation of 90° of each profile following the " Z " axis .

Select the top profile (or the bottom if you prefer !)

After activating the " 3D " function , make a rotation of 90° and show the rotation axis to the base of the profile.

Repeat this operation on the other three profiles.

The profiles are now positioned to receive the surface that will cover them like a tent canvas.

You will now create this surface.

Select all of the four profiles.

Click on the icon: " surface "     then: " smoothed surface " 

As requested in the aid line, give the chaining order and the profile directions.

The chaining order is made by the designation of each profile to give the order in which the surface will be created, if for exampl you designate the top profile, then the bottom one, then one of the two intermediate profiles, you will create a wave surface! (the most usual case is to designate them in increasing or decreasing order).

The direction is the way (left / right) in which the surface will be created; if you alternate the directions you will intersect the surfaces. (rare case except for artistic applications !).

For this example you will designate successively each profile from the bottom to the top starting from the left (or right) but without crossing.

Click on the left end of the bottom profile, then successively on each left end of each profile in increasing order.

After validating the last point, make a right click that will stop the designation and launch the calculation of the surface.