Surfaces creation

Now we got all the points and lines we need, but to create the patterns, we need surfaces we can unroll. First, we need to create some curves which will be the outlines of the surfaces.

Use a new layer. We will start from the tips, assuming that you want to create round tips. If you don't, just skip this paragraph. I use the (Rhino : Curve>Free-Form>Interpolate points) tool, to interpolate the tip outline from sibling profiles. To be more accurate, I'll use two adjacent profiles :

Depending if the adjacent cell is closed or not, for the leading edge outline, use either the chord's start (closed, red points) or the vent start (open, white points). Then, I trim this curve to keep only the tip part of the outline :

Now create the trailing edge outline. Create only straight lines, one per cell, it will simplify the surfaces creation and unrolling. If you want to use round lines, be sure that your CAD tool will be able to unroll the surfaces. Rhino can't, sometimes, so it's better to use straight lines.

And now, the leading edge. There's two cases : open cells and closed cells. For closed cells, we need a single line. I draw this line between chords, so the corresponding unrolled surfaces will be less curved and will be easier to sew. For opened cells, we need to lines, one for the upper point of the vent, and one for the lower point of the vent. As a consequence, we'll get a third case : the transition between a closed cell and an opened cell (from a chord to a vent end).

Now it's time to delete useles curves : vent marks for closed cells, ... Be sure that your curves (upper and lower skin) start and stop exactly at the outline. If it is not the case, you can corerct it easily doing a join then a split with upper skin and lower skin curves. You should have :

Tip profile (closed cell).

Here, intermediate cell between a closed and an opened cell :

Finally, connect together every vent upper point and every vent lower point.

Of course, you could create much more sophisticated vents.

We now have all the curves we need to create the upper and lower skin surfaces. On the next pictures, I've hidden useless layers, and created two new layers : one for the upper skin (purple) and one for the lower skin (green). I start from the tip. Here, I only have two curves to create my surface (if you have a profile at the tip, skip this paragraph). I use the Surface>Edge Curves function :

For the other cells, I use the Surface>From Curve Network function :

Do the same for every cell :

And the cell for the upper skin :

Now we get the surfaces for half the foil. Nice, isn't it ?

If you wants D-Ribs, it's time to create them. All you need to to is to connect the points and create the surfaces the same way you did for the upper skin or the lower skin :

Do the same for every D-Rib. Here, I've created D-Ribs for a 'every third profile' style bridle, but it's not mandatory, of course.

Surfaces are all created. It's time to create all necessary details for the surface unrolling.