Revolution

The Surface->Revolution command in the Model module allows you to create a 3D object by revolving a curve or a face about an axis.

For detailed procedures and examples, see the Revolving a Curve about an Axis section of the Modelling User's Guide.

You can use relational modelling concepts on the objects created using this command. Always make sure that the Preferences->Create Modelling Relation command is activated first.

For an overview of relational modelling, see the Relational Modelling section of the Modelling User's Guide.

Procedure

1. Select a curve.
2. Choose the Surface->Revolution command.
   
   The Revolution dialogue box is displayed.
   
3. elect the resulting Object Type: Polygon, Patch, or NURBS.
4. Select the desired Axis of Revolution.
5. Set the Degree of revolution (range is 0 to 360°).
6. For all object types, set the number of Subdivisions.
7. For patch or NURBS surfaces, set the Step value.
8. Click Close to close the resulting polygon or surface object.
9. Click Ok to create the object or Cancel to exit the dialogue box.
10. If you selected Around Curve as the axis of revolution, pick the target curve.

The result is a 3D object. The curve remains displayed on the screen after the new 3D object has been created, and can be used again to create more objects. Notice that the original curve and the revolved object are on the same spot.

If you are using relational modelling, as you edit, transform, or scale the generator curves, you will see the object simultaneously move and respond to your changes. The only operations that can be performed independently on the generated object are transformations and inversion of the object's surface normals.

Parameters

Object Type

• Polygon: The resulting object is a polygon mesh object. You can specify the number of subdivisions between control points.
• Patch: The resulting object is a patch. You can select Linear, Cardinal, or B-Spline type.
• NURBS: The resulting object is a NURBS surface. You can select Linear, Quadratic, or Cubic degree. For more information, see the Degree and Continuity section of the Modelling User's Guide.

Axis of Revolution

For examples of the differences in these selections, see the Selecting the Axis of Revolution section of the Modelling User's Guide.

• X, Y, or Z specifies on which of the global axes the revolution occurs.
• Free Axis creates a 2-point Linear curve at the global origin lying on an axis at the 45° angle relative to X and Y. The object is revolved around this default axis. You can then transform this default curve to create the desired effect on the generated object.
• Around Curve allows you to specify a target curve as the axis of revolution.

Degree

Allows you to set the value (in degrees) of the rotation angle around the axis specified by the Axis of Revolution parameter.

Subdivision

Sets the number of subdivisions for the latitude of the object.

Step

Sets the resolution of the revolved surface. The higher the value, the smoother the surface will be. This parameter is only available when the resulting object is a patch or NURBS surface.

Close

Applies only if the generator curve is closed and if the revolution is less than 360°.

If you selected the Object Type to be:

• Polygon, the result is a closed polygon mesh object.
• Patch or NURBS, this selection creates a face on the resulting object's top and bottom. The result is a hierarchical object.

Last updated 02-apr-1998