North's proprietary design software creates a custom "mold" file for each individual sail.
Because a 3DL sail stretches less than competing 2D paneled or string sails for a given amount of yarn, North designers can more accurately define the desired "flying shape" because the computer molded shape is that much closer to the resultant flying shape.
Shown here is the underside of a 3DL mold with actuators controlled by a highly complex computer program.
The fiber head "draws" a pattern in yarn that matches anticipated loads in the sail. All structural yarns are applied under uniform tension and adhere to the surface of the film to ensure they remain in place prior to being locked by the lamination.
This second film contains a secondary mapping of yarns to handle incidental loads off the primary load lines.
This causes the laminate to conform tightly to the mold in a manner similar to a shrink-wrapping process. After curing, the sail is allowed to cure further for a full five days prior to shipping and/or finishing.
Because of the inherent material efficiency of the 3DL manufacturing process, a finished 3DL sail can be up to 20% lighter than a conventional paneled or string sail of equivalent stretch.
Or, it can have a wider wind range (larger sweet spot) for a given weight.