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Section of a revolution surface |
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You can use an object existing in the model — an edge, a curve, a sketch (sketch area) or a face, as a section of the rotation element or create a new object — a contour or sketch , without interrupting the operation.
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The existing object can be specified before starting the operation. It will be automatically selected as a section. |
Requirements to a section
•The following can be selected as the section:
•sketch or closed sketch area (see section Using sketches in operations),
•edge,
•curve,
•face.
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Using curves with subordinate curve objects (projection curve, intersection curve, etc.) has specifics. Details... |
•A section can be closed or open-ended.
For a closed section, you can create a closed surface. If the section is open, you cannot close the surface. See the examples of plotting closed and open surfaces in figure Rotation of the face.
•An open section must consist of one contour. An exception is the selection of a curve with subordinate curve objects as a section (such a section may consist of several open contours).
•A closed section may consist of one contour, as well as several closed contours on the condition that one of the contours is external and all the others are nested inside it with a nesting level of 1.
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For a section containing nested contours, only a closed surface can be plotted. If the rotation of the section is less than 360°, to construct such a surface, it is necessary to enable the Close Surface option. When the option is disabled, the surface is not plotted, and an error message is displayed on the screen. |
•When you select a sketch (a sketch area) as a section, note that the contour of the section should not intersect with the axis of rotation (or its extension). However, certain points of the section contour can lie on the axis (or its extension):
•for a closed contour — any of its points and/or sections,
•for an open contour — only extremities.
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If the sketch contains a line segment with the Axis line style (or an object of the Centerline type) among other objects, then when the sketch is selected as the section, this line segment (object) is automatically set as the axis of rotation. If a sketch area is specified instead of the sketch, the axis is not selected automatically. You have to specify the axis manually. |
Setting a section
•To select the existing object as a section, specify it in the Design Tree or in the graphic area of the model.
Features of selecting a sketch and a sketch area:
•to select a sketch, specify one of its objects in the graphic area of the model or specify the sketch itself in the Design Tree,
•To select an area in the sketch, click inside the required area.
•To create a new object (contour or sketch), do the following.
•To plot the contour, press Plot Contour 
button to the right of the field Section. This will start process of creating a contour. Specify the objects included in the contour, and click Create Object.
•To create a sketch, click the Create Sketch 
button to the right of the Section field. This will start sketch placement process, and then the system will switch to the sketch mode for creating geometry. Perform the steps necessary to build and complete the sketch mode.
After completing the contour/sketch creation process, the system returns to the surface plotting process. The created contour/sketch appears in the Design Tree and is automatically selected as a section of the revolution surface.
The name of the object selected as a section is displayed in the Section field. If the section is a region in the sketch, then the sketch name and the word Region are displayed in the field.
If required, you can change the section of the revolution surface. To do that, click in the Section field and select the required object.
If the section is a sketch or a contour, you can edit it by clicking the icon 
in the Section field.
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If during the rotation of the section around the selected axis two or more points of the section have coinciding trajectories, then the operation is impossible. You have to change the section or the axis. |
