Forefoot Control with Corner Wrapping
In hull design, the transition from the stem to the bottom, or forefoot, is an important aesthetic and functional feature. It's important to get the forefoot to have the right shape, and for the stem curve to blend into the bottom with slope and curvature continuity (many programs will only guarantee slope continuity, and a discerning eye can see the jump in curvature).
When working with NURBS surfaces, there is control point in each "corner" of the surface. In this case, we are dealing with the corner between the stem and the bottom, but of course we don't want it to be a corner. The stem curve should "wrap" smoothly into the bottom. The figure below shows a hull with the control points turned on and the corner control point identified:
In the figure above, there is slope and curvature continuity from the stem to the bottom. In the figure below, the corner point has been moved purposely so that there is no longer slope or curvature continuity:
To reimpose the "corner wrap", simply select the Corner Wrap function from the RhinoMarine menu, and click on the corner control point. The surface will now have slope and curvature continuity through the forefoot, as shown in the figure below:
This command is another example of how RhinoMarine can save you time and improve your design.