Surfaces > Swept Surfaces

Creates a new surface by extruding a generation curve along a path curve. Normally used to make tubular objects with symmetrical cross sections.

Extruding a curve

Create a new surface by extruding a generation curve along a path curve. Normally used to make tubular objects with symmetrical cross sections.

To extrude a profile curve along a path curve

Create the curves you will use for the profile and path.
Click the Extrude icon, or choose Surfaces > Swept Surfaces > Extrude from the tool palette.
Pick the curve or curves you want to extrude.
You can select free curves, curves on surface, isoparametric curves, trim edges or even faces.
Click Go.
Pick the path curve to extrude along.
You can select a free curve, a curve on surface, an isoparametric curve, or a trim edge.

The Extrude tool creates the new surface starting at the position of the generation curve and following the shape of the path curve.

Tips and notes

The generation curve does not have to be near or intersect the path curve. However, placing it as near as possible will help you visualize the result.
If you need more control over how the surface is created, use the Rail Surface tool.
This tool works best for closed and/or symmetrical profile curves. If you need to control the twist of the profile, use the Rail Surface tool.
To extrude a face made of multiple curves (for example, Text) as a single object, select it before choosing the Extrude tool.
In most cases, you will want the profile curve to be perpendicular to the starting point of the path.
To accomplish this, use the Plane tool to create a construction plane at the start of the path curve, perpendicular to the tangent. Then create the profile curve on the new construction plane.
If the path curve has severe bends or corners, the extruded surface may have unwanted twists.
To correct this problem, use the Insert tool to increase the number of edit points/CVs on the path curve in the problem areas, so that transitions between CVs are more gradual.

Extrude Options

Style: Tube – As the profile curve sweeps along the path, it pivots to maintain the same angle to the path curve.

Flat – As the profile curve sweeps along the path, it maintains its original orientation.

Create caps: Caps can be created at the ends of the surfaces if the extruded objects are closed planar curves.

Off – Do not create caps at the ends of the extruded surface.

Cap Start – Create a trimmed surface to cap the first end of the extruded surface.

Cap Both – Create trimmed surfaces to cap both ends of the extruded surface.

Extrude Pivot: This option controls which pivot point to use when you are extruding more than one profile curve.

This option appears when Style is Tube.

Closest – Pivot the profile curves around the endpoint of the path curve closest to the bounding box of all the profile curves.

This option is the default. It works best when you have a profile curve near the start or end points of the path curve.

Component – Pivot each curve around its own individual pivot point.

This option works best when you want to extrude text.

Create History: Save the history of the new surface for later editing. If you turn Create History on, you can modify the curves that were used to create the surface, and the surface will update.

Note
If you have an extrude history command built from a face (created prior to Alias 13) the caps will be lost if you update the history.