Not Plane Sailing

Despite the steamship stealing the limelight in the development of international trade in Victorian times, the brunt was borne by sailing ships, at least until the final decade of the 19th century.

Typically these were square-rigged, with most sails rigged across the ship, rather than along the line of the hull like sailing yachts. Steam’s takeover was slow at first, but by 1955 there was not one fully-rigged merchant sailing ship still carrying cargoes. The intricate beauty of their rigging was a stark contrast to the harsh conditions they had afforded their crews.

Wanting to draw some of these long-lost vessels, I first tried measuring up contemporary photographs and engravings. Some years ago I hacked my own CAD/CAM applications to perform rudimentary photogrammetry when developing software to design and construct paragliders. Sadly those have long since passed in the transition to Classic, let alone OS X.

With the Mac so strong on photography, I thought that it should be easy to find a modern photogrammetry application, but was disappointed. It seems that one of the few games in town is PhotoModeler, requiring Windows and costing a small fortune, and OS X has been left bereft of any equivalent.

There are a couple of architectural CAD applications for OS X that offer photogrammetric features, aimed mainly at those needing to manipulate and measure images of buildings: DigiCad 3D and HighDesign Professional. Although I am sure that they are excellent at their job, I was clearly asking something different of them.

So I have found solace in the works of Basil Lubbock, David MacGregor and Harold Underhill, who painstakingly documented these ships’ lines and intricate details in elegiac drawings. It was then a matter of scanning in a set of body plans and converting them into a faired hull, onto which I could build masts and more.

I had purchased Luc Favereau’s stunning l’Aurore for Poser (which sadly seems to have disappeared now), three months of painstaking work that have captured wonderful detail in an 18th century corvette. Sadly for me she is the wrong type of ship and wrong century, but made me realise that trying to create a detailed 3D model was going to be harder than building one in wood.

There were other problems besides: in my quest for accuracy, I realised that much of the rigging changes as sails are set, reefed, and furled, something very difficult to address with most 3D models. I decided that what I needed was the hull, masts and yards alone, so that I could position and light them for each drawing, then complete the detail of standing and running rigging using those cardinal points.

With over 800 applications on my Mac, I had several paths open by which I could turn the scans into a 3D hull. After previous skirmishes, I had decided to construct my final model in Eovia’s Hexagon 2 (now known as DAZ 3D Hexagon 2.5), which unfortunately did not seem to like the DXF output from 2D applications that I could use to trace the lines.

After some experiments, I discovered that the simplest route would be to form curves on a background of the scan, and assemble those into a full NURBS surface in the sophisticated if quirky freeware Blender. Its manual contained a worked example of this, and I soon settled down to driving it via its idiosyncratic keyboard commands and menus.

The surface complete, I exported it in 3DS and .obj formats, which Hexagon happily read. My hull was then fitting out with precisely tapered masts and yards at last, although it had been a twisted and sometimes frustrating course. I am still sorely tempted to put together a little photogrammetry tool so that I can utilise my growing collection of photos of square riggers, although it is hard to tear myself away from reading sailors’ accounts of that era.

squarerig2Hopefully my pictures will do a little justice to those who lived and died on those beautiful ships.

Updated from the original, which was first published in MacUser volume 22 issue 22, 2006. There still does not seem to be a decent photogrammetry app for OS X, or is there?