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Canopy curve

Now, we have to bend the profiles, except if you want a flat canopy.
With Rhino, it's really easy. Draw the canopy curve you want, intersecting with the span line in (X=0).

Both curves do not have the same length (Analyze>Length to compute the length of a curve with Rhino). We have to adjust the length of the canopy line. I use an iterative method (length, compute a ration, scale, length, compute a ration, scale, length, ...) until I get really close. For the scale command, use (Transform>Scale>Scale 3D). I work in millimeters, and stop the process when I get 1 or 2 mm close.
Now it's better :

Now, just bend all the profiles. Be sure to have a backup of your file, because it will be much easier to get the patterns from profiles which are all in the same plane. Use the 'flow along curve' function : it takes a 'backbone' (the span line) and a model curve (the canopy line) :