Surface Modeling - An Automobile Bonnet Part 3 of 3

Project Curve - Direction Step Point the arrow down towards the surface and click. Click Finish on the ribbon bar.
Project Curve - View It If required, click the Visible and Hidden Edges    tool on the Main toolbar to see the projected curve.
Trim the Surface As explained earlier, trim the bonnet surface as shown in figure.
Parallel Plane and Project In the parallel plane, create a line and project it on to the bonnet surface as shown in figure.
Derived Curve Select the Derived Curve    tool from the Surfacing toolbar. Select the two edges as shown in figure. Two derived curves - a longer and a shorter - will be created.
The Recess Sketch Create a sketch in the y-z plane as shown in figure.
The Recess Sketch - Tangent constraint Constrain the endpoints of the curve tangentially to the projected line from earlier step. See figure.
The BlueSurf - First Curve Click the BlueSurf      tool on the surfacing toolbar. Select the longer derived curve as shown in figure. Click accept    on the ribbon bar.
The BlueSurf - Second Curve Select the shorter derived curve and click accept    on the ribbon bar. Both - correct and incorrect - ways of picking the shorter curve are shown. Pick in the correct way.
BlueSurf Appears Click Finish and then Preview. A BlueSurf will be created as shown in figure. This bluesurf connects the endpoints along a straight line as indicated with the yellow dashed line.
BlueSurf Guide Curve Still in the BlueSurf command, click the Add Guide Curves    button on the ribbon bar. Select the curve as shown and click accept
BlueSurf changes Form The BlueSurf changes its form as shown in figure. Select the curve in the middle as shown and click accept
Extend the Bluesurf Next, select the third curve as shown in figure. Click the accept Preview and Finish buttons in that order.
BlueSurf Created A BlueSurf, as shown in figure, is finally created . This surface spans two derived curves and is guided by the sketched curve and the two edges.
Stitch the Surfaces Click the Stitch Surface      tool on the surfacing toolbar. Select the surfaces as shown in figure. Click the accept Preview and Finish buttons in that order. The surfaces will be stitched to form a single surface.
Project Curve – Begin Create a straight line in a plane parallel to the y-z plane. The line is a little above the bottom part of the bonnet surface. Extend the line well beyond the bonnet when viewed from the right.
Project the Curve Project the curve onto the bonnet surface as shown. Even though the line is only on one side of the surface, the projected curve goes all round the surface - even on the other side.
Trim Surface Finally, trim the bonnet surface using the projected curve as the trimming curve. This is the final shape of the bonnet.
Surface to Solid Click the Thicken      tool on the Features toolbar. The Thicken tool is in the same flyout as the Thin Wall and Thin Region tools. Select the Trimmed bonnet as the surface to thicken. Use a small value of 3 mm (sheet metal ?) to thicken in any direction. cMayoCAD is a first of its kind training program where you learn to build your own, brand new, fully functional CAD system using a geometric modeling kernel.