When a luxury yacht is ordered by someone high on the world’s who’s-who list, shipbuilders pay special attention. Outfitting the craft with the latest appointments to attend to expensive epicurean tastes is certainly an important issue, but before the crystal can be heard tinkling in varnished mahogany cabinets, the shape and style of the craft must go from artist’s conception to solid reality.

Photogrammetry, the science of extracting 3-D geometric measurement from 2-D photographic images, is as old as modern photography itself. The day the first glass plates were exposed to light to create fixed images, engineers started scratching their heads looking for ways of using this technology to improve their work. Eventually, it became usual to take images from different positions to obtain views on all three axes, and coordinates could then be calculated.   The methods, of course, followed every advance in photographic technology: from measuring two points on a photograph and multiplying by the scale value; to stereophotogrammetry, or taking images from different positions to obtain views on all three axes, and calculating coordinates. In engineering applications, photogrammetry is mainly used to accurately acquire reference markers, which are then used for direct 3-D measurement or to position a 3-D measurement device. The field has come full circle: the invention of photography prompted the development of photogrammetry, and now photogrammetry stimulates the development of new technology, such as the MAXscan from the Handyscan 3-D line of scanners, developed and marketed by Creaform.

Luxury craft today boast sleek, smoothly curved lines; those free-form shapes are difficult to measure using traditional methods, especially on site. Where the aerospace industry is notoriously stringent on accuracy, naval construction is less rigid; yachts under construction frequently end up not exactly conforming to CAD measurements derived from the original, often hand-sketched, artistic design.

This poses a crucial problem to windowpane manufacturers. Because the as-built data may differ from CAD drawings, fitting curved panes to equally curved metal frames can become virtually impossible. Traditional measuring tools may help out with flat surfaces, but curves of varying degrees are an entirely different challenge.

And that is when the MAXscan gets called in.

The MAXscan is part of the Handyscan 3-D line of laser scanners, the world’s first and only portable, self-positioning, hand-held scanners, capable of creating 3-D models in real time by processing data captured by two cameras. The MAXscan is specifically used for large parts, as it features photogrammetry capability for accurate measurement of the global positioning model. To top it all off, it is a lightweight, hand-held device that anyone can learn to use quickly.

Among its many technical features, the MAXscan was designed to handle large objects, and even a yacht’s 10 m × 5 m × 1.5 m window line falls well within its range. With an accuracy of 0.2 mm on such a project, the MAXscan clears the question of attention to detail.

The MAXscan and other Handyscan 3-D scanners have an additional ace up their sleeve: they can work in teams. Since the MAXscan measures the global positioning model using photogrammetry, the same highly accurate model can be used by any other Handyscan 3-D scanner for positioning. Using a MAXscan in conjunction with another Handyscan 3-D scanner such as a REVscan or an EXAscan can halve the time it takes to scan a large and complex part.

As for file formats, the MAXscan outputs a triangulated mesh in STL format, the file format most used for rapid prototyping and computer-aided manufacturing. This format describes a raw unstructured triangulated surface by the unit normal and vertices of the triangles using a 3-D Cartesian coordinate system. The resulting file can then be treated with all major reverse engineering CAD software. Post treatment allows windowpane manufacturers to design perfect CAD files of individual craft under construction using the exact physical replica, and perfectly fit the panes at last.

The luxury yacht can now boast an airtight, aerodynamic cabin as sleek and smooth as the original drawings promised.

The MAXscan is a two-in-one tool, capable of scanning and creating photogrammetric data at the same time within a limitless working volume in a merge-free, one-step process. The Handyscan 3-D line of products from Creaform also features the VIUscan, to scan, shape, and texture; the ERGOscan, for medical applications; the REVscan, for general reverse engineering and quality control work; the EXAscan, for work calling for extra precision; and the UNIscan, the entry-level general practitioner.