How To Modify The Loft Created By Controlling The Sketches.

We will practice how to modify the loft created by controlling the sketches.

1. Start by SKETCHER workbench. You can do that by double click in one of the SKETCHES in the STRUCTURE TREE. (Don’t try to select a plane and use the Sketch button since this will not allow you to enter the sketch but it will create a new one.)

2. Once you enter the Sketch use your mouse to drag on the points of the spline. This will modify the shape of the spline and consecuently the shape of the LOFT.

3. While the spline in the sketch changes you will notice that the loft turns to a bright red color. This indicates that there has been a change in one of the entities that defines the surface, they haven’t been translated to the surface, in other words the surface needs to be updated. You will update this surface on the Generative Design Workbench once you exit the sketcher.

4. Click on the exit button if you are satified with the changes to return to the Generative Shape Design environment.

5. Once you exit the Sketcher you will see how the spline has been updated. However depending on your CATIA settings the surface might still keep it’s previous condition.

6. Click on the local update button to update the modified parameters. You will see how the surface is now updated to the according to the modified parameters on the sketches. If the parameters are incorrect you can make the necessary adjustments jumping back and forth between the Generative Shape Design and the Sketcher Worckbenches. Until you define the final surface.

7. You can define more planes and Sketches on order to expand the possibilities in the design. By adding more splines and more sketches.

8. Repeat the process until you find a solution.

Note: The same principle can be used to make revolved surfaces with one straight line as an axis of revolution and a spline as a profile.