Using Guide Curves with Sweeps
Sweeps are features that use a closed 2D sketch that is “swept” along a path. Two sketches are generally needed to generate the Sweep though the path can consist solely of the edges of a model. The open or closed sketch path can either be a 2D sketch or a 3Dsketch, but the 2D profile sketch and path must be located in different sketches.
The sweep path does not need to intersect the profile sketch, but the path needs to at least extend to the plane that the sketch is on. In Fig. 1, the first figure will fail because the path (bent line) does not intersect the profile plane. The second example however will sweep as expected. If the sketch profile and path are on the same plane the sweep will fail because a solid model will not be formed. For example, in Fig. 2, if you were to sweep the circle to the right, the profile would be infinitely thin and it would intersect itself.
An example of a simple sweep is shown in Fig. 3. Notice in the Design Explorer that the profile and path are in different sketches. The profile (square shape) is sketched on the XY plane and the path (bent line) is sketched on the YZ plane. Fig. 4 shows the dialog box with the selected items. In this example, the path was a 2D sketch but it could have also been a 3D sketch.
The Sweep Type has two different options and allows you to sweep the profile the entire length of the path or only up until certain geometry is reached. Obviously, each option would be suitable for different applications. If a design is going to change, but you always want the profile to sweep to some geometry, you will want to use the To Geometry option. In this simple example, the path for the sweep extends through the entire part but it only sweeps to the front face that is populated in the Selected Geometry portion of the dialog box.
Sweep using geometry as the path
Sweeps can also use the edges of existing geometry as the path. In Fig. 7, the profile sketch was created on the top surface and the edges of the model were used as the path. Since Alibre Design is parametric, if the dimensions of the original features are changed then the Sweep Cut will change automatically.