To Create a Surface by Lofting Section Elements

Select the Loft Surface tool ( Modeling > Surfaces > Create Surfaces > Loft > Loft ).
To create a parametric surface, turn on Parametric.
Note: Creating a parametric surface is the ideal thing to do, as it will let you edit it easily without needing to be manually rebuilt.
Select the first section element.
Select the second section element.
(Optional) Use <ctrl+data point> to select further section elements or hold down the Data button and drag a line to select the profiles. Pressing the <Alt >key changes the selection to a rectangle.
Enter a data point to view the surface.
(Optional) Modify the profiles. With closed profiles the direction of the red arrow can be changed and the location can be moved by dragging the rotation ball.
Enter a data point to accept the surface.

The Data button is depressed and a selection line is used to select the profiles. Force Start Point at Selection Point is on so that the endpoint of the curve closest to the selection line is used.

During the preview state, the red arrows can be adjusted. With open profiles, the direction of the arrow can be changed. Generally, the preview displays what will be generated. If the preview does not display, then the arrows need to be adjusted.

With Segmented Loft and Simplified Section Curves turned off.

With Rebuild Profile Curves on, each section element is approximated by a B-spline curve, with the resulting surface being smoother. The dark blue profile curves show the difference between the original definition.

With Segmented Loft on, each change of the profile results in a planar surface.

A loft can be made between two surfaces or solids or a combination of a starting solid or surface and a system of curves between. In this example two solids are used to loft between two edges.

When an edge of a solid or surface is selected, the two arrows display; a red arrow changes the direction of the selected edge and a green arrow selects the face. The green arrow on the slab points down indicating that the vertical face is used to make a tangent transition.

By clicking on the green arrow on the slab, the top face is used for Tangent Continuity.

Start and End Continuity are set to Tangent.

Start and End Continuity are set to Position, creating a sharp change between the surfaces.

As the arrow is relocated the preview updates showing the final geometry when accepted.

Enter a data point to Accept the final result.

The one arrow that is pointing up can be rotated by dragging the rotation ball to be in line with the others.

To Create a Surface by Lofting Section Elements

The Data button is depressed and a selection line is used to select the profiles. Force Start Point at Selection Point is on so that the endpoint of the curve closest to the selection line is used.

During the preview state, the red arrows can be adjusted. With open profiles, the direction of the arrow can be changed. Generally, the preview displays what will be generated. If the preview does not display, then the arrows need to be adjusted.

With Segmented Loft and Simplified Section Curves turned off.

With Rebuild Profile Curves on, each section element is approximated by a B-spline curve, with the resulting surface being smoother. The dark blue profile curves show the difference between the original definition.

With Segmented Loft on, each change of the profile results in a planar surface.

A loft can be made between two surfaces or solids or a combination of a starting solid or surface and a system of curves between. In this example two solids are used to loft between two edges.

When an edge of a solid or surface is selected, the two arrows display; a red arrow changes the direction of the selected edge and a green arrow selects the face. The green arrow on the slab points down indicating that the vertical face is used to make a tangent transition.

By clicking on the green arrow on the slab, the top face is used for Tangent Continuity.

Start and End Continuity are set to Tangent.

Start and End Continuity are set to Position, creating a sharp change between the surfaces.

The one arrow that is pointing up can be rotated by dragging the rotation ball to be in line with the others.