CATIA has its roots in the aerospace industry, where elaborate and highly-controlled surface quality is a must. As a rule, the simpler the surface construction method and parent geometry, the better its resulting quality. And good surface quality means better solid-model construction and change implementation. This is one reason that we have chosen a circle-segment arc as the basis for our top surface of revolution.

To create our surface of revolution, we will use the `Wireframe and Surface Design´ Workbench found under the Mechanical design list.

 WORKBENCHES TO BE USED: Sketcher Wireframe and Surface Design Generative Shape Design

 Revolution Extrude No Show Switch No Show Quilt (Skin) Trim Surface

1. We wish to create a basic rectangular button face from our wireframe sketch. There would be several ways to do this, and here a basic hybrid modeling approach will be demonstrated. Our basic shape will be derived from CATIA V5 parametric surfaces, and the final part closed into a solid in the next lesson.

For our button face, we will use a surface of revolution. Circles create very simple and stable geometry, which is important later on when making modifications.

To create a revolution surface, simply a) select the arc created in the previous lesson, b) select the H-parallel line as rotation axis c) enter parameters of 10 degrees and 10 degrees. CATIA understands that the second parameter, when given, runs in the opposite direction.

2. For the sides of our button, we will use an extruded surface from a rectangular profile. Using the Sketcher Workbench, we will create a centered 20 x 12 rectangle on our xy plane, parallel to the H and V directions. Once leaving the sketcher, we will use the extrude function, available under the Generative Shape Design Workbench, to create a rectangular surface through our revolution surface that is 10mm long. Now, using the trim surface function, we will cut the inside of our revolution surface to our rectangular extrusion, and vice-versa for the bottom half of our rectangular surface.

The resulting trimmed faces should then be joined into a collective `quilt´ (similar to V4 `skin´ entity).