Creating Linear Sweep surfaces with a Draft Angle

The following step-by-step example describes how to use the Linear Surface command to create linear sweep surfaces with a draft angle. Once you have selected the Linear Surface command, proceed as follows:

1 To obtain an associative surface, that is an open solid — a Skin —  retaining a link to its base curves, so that if you modify such curves the surface will be modified accordingly, check the Associative Mode box. See " Associative Surfaces (Skins)" for details.
2 Select the base curves.




As soon as a curve is selected, the preview of the corresponding surface is displayed



Each time you modify a parameter, the preview is also updated.
To change the selected curves, right-click on Curves in the selection list, select Reset in the context menu and perform selection again.
3 In the Draft drop-down list select Angle. In the Angle mini-dialog box, now displayed on the model, type the value of the draft angle to be applied to the resulting surfaces (alternatively, you can drag the corresponding handle, circled in red in the illustration below):

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4 Under Direction, select the sweep direction type from the drop-down list. For details, see "How to define an axis or a line".
 
5 In the Extent drop-down list, select the way the extension of the sweep path has to be specified:

Length Applies a constant length along the sweep direction.
In the Length mini-dialog box, type the length of the path, or drag the two circular handles at the end points of the path to interactively set the path length.



See "Continuity at transitions" for further details on what happens when using the Length mode if some base curves are not planar.
 
Height The height of the path along the sweep direction. When the base curves are not plane, the height value is computed starting from an "average plane".
In the Height mini-dialog box, type the height of the path, or drag the two circular handles at the end points of the path to interactively set the path height.
If the base curves are plane the Height and the Length options work exactly the same way. To better appreciate the different behaviors of the Height and Length options, see "Comparison between the Length and the Height mode".
From-To To define the path through an initial and a final surface. Click From and select the surfaces you want to start from (if the base curves are planar, their plane is the default starting surface), then click To and select the surfaces you want to end at.
To avoid undesired results when you select the From-To option, make sure that the projection of the base curves onto the ending surface in the sweep direction is "contained" in the surface itself.
6 Clicking on the More Options item in the selection list, you will be enabled to:
7 Click or to confirm your selections and create the surfaces.



Click to discard your changes.

Self intersections
When the draft angle and the height are such that the resulting sweep surface would have self intersections, the self intersections are automatically trimmed and no error occurs. See an example in "Self intersection management when the draft angle is not zero".

Warnings about troublesome situations when the draft angle is not zero

If some problems are detected when creating the surfaces, a special warning icon is displayed in the graphics area:

And a specific label indicating the type of issue is displayed on the model in the position where the problem occurs. You can hide the label by clicking on the previous icon, that will turn to:

See an example in "Managing Warnings".

Tips and Tricks
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