Numerous axially symmetrical objects can be created by rotating a profile shape around their axes. Some examples are drinking glasses, bottles, a winding staircase or even a snail’s shell. These shapes can be created using the Lathe object in conjunction with a Spline object. In our example we will create a
Creating an outline
You can either create the outline manually or first create the outer line and use the
These points can be further edited by dragging the handles at the end of each tangent. If you want to create a small curvature, using the Chamfer function would be the best option. To do so, select the points you want to chamfer and select the
Once you have shaped the Spline to fit your needs, create a
The overall shape of the object will be influence by the location and number of Spline points and by the Subdivision value. In the image below you can see how the level of detail is increased when the Angle option is set from Adaptive to Subdivided mode. Increasing the Angle value will reduce the number of surfaces at the small chamfers to a reasonable number.
In the next image you can see how the Lathe object object’s Subdivision value can be used to increase the number of surfaces that run in the direction of rotation.
Creating unusual shapes
Often, shapes must be modeled that are not closed or comprised of simple rotation objects, e.g., a baking form or the rail of a spiral staircase. This is something the Lathe object can handle as well. The Angle value can be used to generate rotations of less than 360°, as shown in the image below. At the left of the image you can still see the open endings of our Spline Object - no cap surfaces were generated. This can be corrected by simply closing our Spline object. To do so, simply enable the Spline object’s Close Spline option in the Attribute Manager. How to fine-tune the Generator object’s caps surfaces and edges was already explained above.
The Lathe object Movement value can be used to offset the Spline during rotation. Entering an Angle value of greater (even far greater) than 360° can result in interesting shapes being created, as shown in the image below. The Scaling value can also be used to modify the scale of the Spline shape in the course of the rotation. These methods can be used to, for example, model a snail’s shell or a screw.