In this "how-to", I will attempt to illustrate how to make a scale drawing from simple photographs taken of a building. For this example, we'll use my grandfather's blacksmith shop in Turin, Iowa. The goal is to get the drawing, and thus the model, as close to scale as reasonably possible. The smaller images may be clicked to enlarge. The first task, as with many prototype projects, was research, in this case, gathering photos and a little information about the building. Ideally, it would be nice to get a photo taken from the front,back, and both sides, showing the whole building. It's also nice to have close-ups of any special details and an indication of height somewhere in the picture, like you or a relative. You will probably not have this luxury, unless you are the photographer. If you are there taking the pictures, you might as well get some measurements if you can get that close to it. With the Turin Blacksmith Shop, at least until someone can get there and get some better photos, we only have a good front view, a partial side view, and a front view with people for height reference. I also have a little history, as well as modeling ideas from an earlier image in this newspaper article. The lower photo is the shop, and Jens Paulsen, mentioned in the article, is my grandfather, who passed away at a young age, before my own birth. I have some more information on Turin and the blacksmith shop maintained on this separate page. Click here to view a larger copy of this image. Armed with this information (thanks Mom!), the next step is to extract the information in the form of measurements. I printed the scanned photos and used dial calipers to take the measurements. You could use a plain scale (a ruler) as well, and it should prove accurate enough for our purposes. I like the calipers because they can be used to transfer the measurement to paper, and the decimal divisions are easy to work with. The measurements can be transferred to a crude hand drawing. Graph paper works well for those who are challenged in this area, like myself. The drawing is made as the measurements are taken, so it comes out 1:1 from the photo. It doesn't matter what it looks like, as this is an interim step. You may wish to save it for reference, but it will not be the final drawing. I used the best photo (above, center) for all the measurements of the front. Measure as accurately as possible, but there will be some rounding in the end. There are also distortions in the photographs that you will have to "fudge." In this case, all vertical measurements were taken from the top, and horizontal measurements from the left side. I use the top as reference because the ground is uneven and the left because it's taller. Measure all the dimensions of the building itself, and all the details you want to model, such as door, windows, chimneys, roof lines, gutters, etc. Make a mental note and measure anomalies, such as the left door in these pictures, which is wider than the right. The next step is probably the hard part for those who feel grumpy about math. We need to determine what scale the drawing we just made is, so we can label all the measurements in what we believe them to be in actual 1:1 feet. It's not likely our drawing will come out to exact HO scale! That's why I do an interim drawing (it also gives us a nice place to scribble without messing up the finished product). We have to take a measurement of a known commodity in one of the photos, in this case, my father. Bet he didn't know he was a commodity! He's about 5 ft 9 inches. We gotta do sumpthin' 'bout that. That's just too hard to work with, but easy to convert. 9 inches, just happens to be 3/4 foot, which is .75 ft, so 5 ft 9 in = 5.75 ft. That's better. Next I measure him in the photo, and part of the structure behind him, in this case the door height. He measures 1.25 in and the door 1.75 in. So we use the formula: Known item is the item in the photo that we know the real height of (my father) Unknown item is the item in the photo that we don't know the real height of (The doors) By use of cross multiplication and division, we find the height of the door is 8.05 feet. We probably have a little distortion or measurement error in the picture, so we will just call it 8 Ft. To simplify the math, you can just multiply the unknown item (as measured in inches from the photo) by the known item (as measured in feet in the real world). Then divide the answer by the known item (as measured in inches from the photo). The answer will be in feet. Example: 1.75 X 5.75 = 10.0625. 10.0625/1.25 = 8.05 Feet. Now that we know the door is 8 feet tall, and on the rough drawing (and the photo we are taking measurements from) it is 1.6", we can surmise 1.6" = 8 feet. If we divide both sides of the equation by 8, we get a more manageable .2" = 1 foot, or you can divide both sides by 1.6, and you will find 1 inch = 5 feet. Because you are allowed to do an operation to one side of the equation, as long as you do the same to the other, both are true: Had the photo with my father and his handsome sons not been on hand, the math would have been simpler, but based on an assumption and therefore less accurate. I could have guessed the door at 8 feet or a window size. With the door, I would have been off a bit by assuming the inside was 8 feet, not the whole door to include trim. I would have gone straight on to surmise the measured height of the door opening of 1.540 = 8ft. So .1925 inches would equal 1 foot, or 1 inch = 5.195 feet. Probably not a big error by the time we round things off. So, now that we know .2 inches = 1 foot, we can convert the measurements from the photo to feet. This can be done by dividing actual measurements taken from the photo by .2 or if you are using 1" graph paper as I did, you will notice that 1 minor division is .5 feet, 2 minor divisions is 1 foot, etc., so you can just eyeball it. Note that as you divide by .2, the number gets larger. Example: I measured the building height at 3.140 inches. 3.140 X .2 = 15.7 feet. The Final step is to redraw it "in scale" or, at least, make a drawing that shows what size the model will be in scale. For this final step, you can use plain paper, graph paper or computer software. I chose to use a Linux program called Xfig. I chose Xfig, because it's an easy to use, powerful CAD program, and it has a nice benefit of exporting to pdf, which prints at the correct size without meddling with it. In my opinion, if you don't have access to a decent CAD program, graph paper is the next best choice. If you use plain paper, it would be advisable to use a protractor or a square to ensure the 90 degree corners are reasonably square. Once you decide how to do the final drawing, it's simply a matter of using your scale ruler to draw out the lines to the right size in your scale or, if you are using a computer, you just have to divide by the conversion factor for your scale (that's just the ratio 1:whatever). For O scale, divide actual feet by 48, HO divide by 87, and N divide by 160. You can find more scales at the NMRA website. Since the intended result is a drawing that will be the same size as the structure you are building, it is not necessary to label each dimension. It may be a good idea to label a few of them and/or place a 1" line and indicate how many prototypical feet it equals. This is important to do if you are working on a computer, so you can verify the size has printed correctly. If you are interested in building this blacksmith shop, I will place the drawings for the other sides, as well as any updates here. There is already a more recent photo. You can download/view/print the pdf version of the above drawing here. Special thanks to Dick (absnut) and Shamus for editing, inspiration and encouragement, as well as to my parents for providing childhood memories of Iowa, the photo images and the documentation. The latest beta version of this ongoing project may be viewed at http://www.ultimatejeep.com/monon/proj/turinblacksmith/scaledraw.html -- http://www.the-gauge.com http://www.ultimatejeep.com/monon