: I would like to learn how to unfold panels by hand calculation instead of
: with a computer -- just for fun. More specifically, I'd like to take a
: kayak I have designed and figure out from those plans how to create panels
: for stitch and glue. Does anyone know of any good online sources for
: learning this process? Or books that cover this?

You can look at the panels of a S&G kayak design as consisting of many small square and some triangular elements glued together, by making a grid on the kayak with the grid points on the lines defined by where the panels meet. Problem is, the 4 points of each of these elements don't lie in a flat plane, because the panels are warped to achieve the kayak's shape. So just to map a single element to a flat panel shape, requires a weighted approximation and projection.

I wrote my own software for this where I first enter the cross section coordinates in a matrix, then interpolate the lines around the panels in order to get smaller elements, create these elements, center each around the origin, perform an SVD (singular value decomposition) to project it on a flat plane, then combine all flattened approximated elements together into a flat panel. I designed my kayak this way, and the math apparently worked fine.

That's how you go from a 3D model to 2D panels. If you know a simpler method to do this and are able to do it by hand, I'd be really interested to know how. Why not use a computer ? That's what they are good for. If you need the software, just let me know.

Henk.