Measure and remeasure

I realise that the title of this post may as well be the same as the title of the blog. But sometimes, things need to be measured again, even after they've already been finished. 

Earlier this week, I learned about First Article Inspection (FAI) for the first time. Of course, I was already aware that such a thing must exist, but I didn't know the name for it. In order to teach myself about it some more, I wrote this short introduction to FAI, which was made easy thanks to Verus Metrology Partners and their 3-step plan. FAI is in many ways at the essence of why industrial metrology is important, but it also shows that things which have already been measured need to be measured again. Of course, you expect all your machines to be properly calibrated; to be accurate and precise. However, just the right calibration won't be enough, so we use measurement to be sure. 

I came across an article about something else that proved to involve a lot of measurement: Guildford Castle (pictured above). Originally established right after the Norman Conquest of 1066, the ruined keep that's dominant today dates from the 1130s and has seen a lot of history. The 12th century also happens to be one of my favourites when it comes to military history, and I will take any chance I get to talk about castles from this era, as they were undergoing massive changes thanks to the advances in warfare and siege engines. 

Nearly nine hundred years after it was first built, it has been extensively remeasured, this time by Historic VR. The entire ruin and its surroundings were extensively scanned using a LiDAR system from FARO. The goal was to not only reproduce the ruin as a virtual model, but to give an impression of what it may have looked like back in the 12th century. Largely basing the imagery off the renovation of Dover Castle's interior, they managed to create a vibrant, digital version of Guildford Castle, and you can experience it for free here (if you have a VR headset). I also recommend this article by capturingreality.com, which has some wonderful sliders showing the scan vs the reconstruction. 

Of course LiDAR is a very modern way of measuring, but although the ruin may not look as impressive as it once did, it certainly involved a lot of measurement. In the Middle Ages, however, measurement was not standardised as we understand it in our post-metric world. Rather than standardising measurements nation-wide, they were standardised per construction site. Inches, yards and feet were known, but all relied basically on one valuable item that the master builder carried around. 

The yardstick, also simply known as a measuring rod, was the one rule that the entire construction site had to abide by. In essence, it's a lot like a modern yardstick that may be used by a cloth retailer. Except the medieval version would have been handmade, with kerfs in it to show inches and feet, with the full length of the stick being that construction site, or that specific master builder's, yard. By keeping to this one rule, the vast range of carpenters, masons, stone carvers, blacksmiths etc would avoid major discrepancies when their separate components came together. In theory, by taking enough measurements of a building, it should be possible to reconstruct a specific yardstick, although I don't believe that's actually been done before. 

Of course most archaeological finds get measured by archaeologists, long after they were initially manufactured. But it's interesting to see how modern technology, such as LiDAR, can assist in reconstructing something that was already built and measured with precision nearly nine hundred years ago. Especially when you consider that FARO's systems have also been used extensively in aiding modern construction, such as in the case of Columbia College Chicago's new student centre.