Diana, Princess of Wales Memorial Fountain, London

September 6, 2004

   The memorial, unveiled in Hyde Park this July, comes as a result of groundbreaking 3D technology and computerized production previously available only to the automotive industry. Now, the architectural world can create mass-produced stonework quickly, and in any combination of complex shapes and textures.
   In only 32 weeks, 520 tons of British silver-grey De Lank granite from the western county of Cornwall were transformed into 549 unique pieces to create a 9.8’/3m- to 26.2’/8m-wide elliptical watercourse with a circumference of 688.9’/210m. The design includes complex surface details, mimicking the intricate patterns of natural forms such as ripples of sand on a beach.
   The project could’ve been hand-carved. But traditional methods wouldn’t fit time and financial constraints for the £3.6 million (US $6.6 million) project; one estimate shows that, in the seven months allotted for manufacturing, 360 full-time stonemasons would be needed to finish the stone using traditional methods … and the financial impact would easily break the budget
   Gustafson Porter, an international landscape architectural practice based in London, created the design for the memorial. It began with a freehand drawing of the shape and a description of the complex textures, patterns and water features on its surface to make water tumble, cascade, curl and bubble as it flowed through its course.
   Initially, designers Kathryn Gustafson and Neil Porter fashioned a clay model of the fountain and, from this, a rubber mould was made and a cast produced. The cast was digitally scanned by the Ford Motor Co. to create a 3D file; this enabled the designers to create sections through the memorial’s granite ring and surrounding land to develop the design of the features in more detail.
   The Diana memorial project is first time the software’s been used for architectural purposes. It had to be adapted from its usual automotive industry applications.
   Surface Development and Engineering, a Basildon, England-based firm specializing in high-quality computer-generated surface models, developed the design into the final smooth 3D model. The company created the digital model of the full shape of the memorial, resulting in a seamless electronic file detailing the exact shape and location of each of its 500+ stones.
   This 3D virtual model became known as the “jelly mold.” It incorporated the detailed design cues and all the engineering and technical restraints involved, with divisions into individual stone blocks for the stonecutters.
   While the shape of the memorial had been digitized, the challenge of physically creating the many complicated textures and patterns remained. The solution came from Texxus Ltd., a London company specialising in textured surfaces.
   Texxus, founded in 2002, faced the challenge with the Diana memorial of digitally modelling 3,982 ft²/370m² of unique surface patterns and merging their software with the jelly-mould software. The outcome of this groundbreaking technical effort was a set of complex computer files that described, with engineering accuracy, the precise shape and surface texture of each piece of stone in the memorial.
   Meanwhile, stonemasons S. McConnell and Sons of Kilkeel, Northern Ireland, needed all their machines to be able to understand this advanced software. McConnell had already worked with scanned shapes from real models and produced identical pieces of stone for high-profile projects. Now, the company had to produce stone to match a shape on a computer file.
   The existing OMAG S.r.L. CNC production center at McConnell was reprogrammed and could handle the files electronically. But when the first designs arrived and the first piece of granite was put on in mid-2003, the first tool wore out after cutting one section of stone.
   The OMAG alone, even with longer-lasting tooling, wouldn’t be able to complete the project in the allotted time. The solution reached was to change some of the designs so that they could be carried out on CNC saws. McConnell bought two Terzago Macchine S.r.L. saws (a Plana and a Forma) and another company – Vero International Software of Gloucestershire, England – developed the software to enable the saws to produce the necessary shaping..
   In just two weeks new tools had been produced for the Omag and the Terzago saws. The first saw was installed by the end of June 2003 and the second one month later, both using the new software that could turn the Texxus designs into reality in stone.
   By the end of August 2003, McConnells went to production shifts with the three machines operating at a minimum 100 hours a week – with manpower needed in the yard 21 hours a day as stone came in from Ennstone Breedon Ltd.’s quarry in Cornwall. Two extra CNC machine operators also came on board.
   Despite the tight deadline, not all of the computer files from the designers arrived on time. “But the (completion) date never moved for us,” says Glyn Lucas, who was in charge of the production workshop for the memorial at McConnell. “The expectation was that we would meet the deadline whenever they gave us the drawings.”
   On one occasion when drawings were late, the stonemasons received a suggestion that they order oversize stone in order to have the blocks ready when the designs came in. However, some of the stone pieces were already taking several days on the machines.
    “An extra 20mm on the block could be hours extra on the machine,” Lucas says. “When you multiply that by the number of square metres we had to work …..
   “The final date I gave them was December 15. I told them if we didn’t have all the designs by that date, we could not produce the stone by the deadline. The final files arrived in January and we started working almost around the clock. We finished on time.”
   The only part of the process carried out by hand-held pneumatic tools (rather than by computer-controlled machines) was a dolly-punch finish. This was added to the curbs at the edge of the watercourse to aid slip resistance. The water in the memorial is only up to 7.8”/200mm deep but the original design allowed for the public to paddle in it.
   McConnell representatives say the company made no profit from the project because they had to buy two new machines and adapt them to perform like routers; the software alone cost $74,000/£40,000. But the legacy of the project is a unique capability among stonemasons because they, in partnership with Texxus, can now offer the most sophisticated level of stoneworking to any architect.
   The Diana memorial story wouldn’t be complete, however, without noting the fountain’s now-world-famous dry run. In the days after the official dedication by Her Majesty Queen Elizabeth on July 6, the fountain ran into several problems with drainage and people slipping in one part of the structure.
   By the end of July, the Royal Parks – a division of the British government’s Department for Culture, Media and Sport, and the overseeing agency for Hyde Park – closed down the fountain. The fountain reopened on August 20 after repairs, mainly for drainage and pumps, and a slight roughening of a stone area where a few people slipped. None of the problems, however, stemmed from the computerized production.
   “As far as we are concerned it’s still a beautiful piece of work, says Norman McKibbin, McConnell managing director. “We made it, but how it's used is not the stonemason's province."
   Claire Santry is a free-lance journalist based in the United Kingdom, specializing in architecture and natural stone coverage for several international publications.