Hello, I was wondering if it is possible to scale a table from a photo. I am interested in finding the dimension of the pedestal and legs from the attached pic. I want to build this for my sister but I really don’t want to guess and screw up the look. Any help would be appreciated. The only dimension they give is tabletop diameter at 36″.
-Jay
Replies
If you have Photoshop, you can match the top width to 36 inches, then scale off the parts you want dimensioned. The picture doesn't have too much perspective, so it should scale fairly closely. If you don't have Photoshop, I could probably send a marked up version of the picture to you, let me know.
Actually, I don't have Photoshop on my computer. If you are willing to send me a dimensioned picture that would be a great help. I appreciate you taking the time to do it. Thanks.
-Jay
Jay, looks like I got to it sooner than I thought. The table seems to be bar height. Let me know if the picture comes through legibly.
Wow that is really cool. Thanks so much for taking the time to do it.
-Jay
Jay, when you build that table, post it so we can enjoy the results. It was no big deal, it would have taken longer to explain it than to do it. It actually took longer to figure how to post it than to do it, as well.
I cannot open your Jpg for some reason but I agree with your post. Sort of..
I will take some standard dimensions of 'typical' works..
As in something like
http://www.highlandwoodworking.com/library/furnituredimensions.pdf
There are many you can find out on the Web.. I do the largest object and then try to find a fit for the smaller object.. Table then the chair.. Not exact science but will give you a idea of the general sizes.
And then find the general sizes of something else in a picture if any. Maybe a door or floor to ceiling.. Whatever. Can be time consuming but also fun at the same time to see what you come up with.
I could be wrong!
EDIT: May and probably will never work if you need exact sizes. But why exact? Scale is better looking for where the finished piece will be placed?
Edited 10/5/2008 9:21 pm by WillGeorge
Jay, I finally got the program to accept the picture, here you go. There is a little uncertainty, but its pretty close. Good luck !
There are a number of "onscreen ruler" programs which put a ruler on screen to measure objects in pixels.The ones I use are:Linux: KRuler
Windows: JRuler.I don't do Macs.These programs can be useful to resize a picture before pasting it into a CAD drawing to trace over. (If you're starting clean, better to trace first and then scale).
Thanks to everyone that offered help to my problem. I always know someone will have an answer in this forum.
-Jay
Very cool. Just used it on pieces I built and photographed (known dimensions) and it worked like a charm. Even delt with perspective effectivley (close enough for me at least) ...Thanks alot...Jimmy
Jay,
Yes, it is possible, as long as an overall dimension is known. Some interpretation will be necessary, since the base of the table in the photo is not shown straight on.
I use a dial caliper (reading to .001") to measure a part of the table in the photo, where I know the dimension, and divide the dial caliper dimension, by the known dimension. For instance, say the table in the photo is 30" tall and measures 3" on the photo, you would divide 3 by 30 and come up with a factor of .1. You can then take that factor and divide other measured dimensions to come up with their actual size. So, if the top in the photo, measured with the caliper is .113" thick, its actual dimension is 1 1/8"( well, really slightly over) .113 divided by .1 = 1.13".
I usually make a factor for both the height and the width, because there is typically some distortion in the photos.
In this case since it is a pretty simple piece, you should do very well with the figures you get, but you may want to double check them, by drawing the table out full size, or to scale.
Rob Millard
http://www.americanfederalperiod
Edited 10/3/2008 4:55 pm ET by RMillard
Hi Rob, your method makes sense to me and I will give it a try. Thanks for the explanation.
-Jay
Jeffrey P. Greene American Furniture in the 18th Century has a very good chapter that discusses measuring from photos. It shows clearly how to deal with issues of perspective. This is a Taunton book, from 1996, so you might also check to see if their is a FWW article from about the same time. I vaguely recall such a thing.
Edited 10/4/2008 4:11 am ET by SteveSchoene
FWW May/Jun 2004 Pg 59 has an article on this subject by a woodworker/architect. It seems complicated and needs a drafting table.
I have it Pdf format but am not sure if it is legal to send it to you.
Maybe someone can comment on that subject
Thumbnailed did a nice job scaling the table but I believe he made a fundamental initial error. His drawn diameter is taken at an angle from horizontal. That is, his is going in and out of the two dimensional plane of the photograph. A more accurate place to start is to measure the table diameter exactly horizontal. This measurement does not change with perspective. The end result affects all other dimensions. I've enclosed a photo showing what I mean.
The top, even at an angle, if scaled to represent 36", will still give you an accurate dimension for everything in the same direction, because it is proportional. The height was measured on a line I didn't leave in the picture, dropped plumb through the center of the table (at the intersection of the pie-shaped top veneers visible in the picture), intersecting a perspective line through the center of the feet. As I said, there's a little uncertainty, but I maintain its certainly close enough if you're not making a museum reproduction.
Addendum : I just looked at your picture,after writing the above. Rather than deleting this , I am leaving it, and confessing error. You are absolutely correct. The widths would be close, by proportionality, but the height would be thrown off. Mea culpa, and thanks for correcting me.
Edited 10/5/2008 9:21 pm ET by thumbnailed
There are a number of different ways to acheive the desired results, but they all have their roots in photogrametery, the analysis of photos to determine acurate measurements. There are any number of texts available on the subject, and any of them will help you figure out this interesting puzzle.
On the practicle side, other than the desire to reproduce something you've seen in a picture, there is at least one lucrative reason for knowing how to accomplish an accurate reproduction. I once had a commission to build a chess table for a friend who had lost the original in a house fire -- all he had left was a photo. It was a challenging project, but the client said my replacement was just like the original, and the insurance company didn't argue over the cost. Not an uncommon circumstance, so it's handy to know how to do it.
Once I realised my error, I could easily have set the full-on tabe width at 36", to get the height accurate, then skewed and contracted the width to match the perspective line, to get close to correct widths. The way I set it up gave me close widths, but distorted heights. In terms of getting the correct figures for both, I think it would have been simpler to just do both scalings seperately. Sorry for the brain fart, Jay! Good thing there are a lot of people paying attention.
Looks like I'm a little late on this, but I believe SketchUp has a feature that's supposed to make it easy to make a SketchUp model from a photo. When you locate the feature and then find yourself saying, "Now what do I do?", look on YouTube for Google's series of SketchUp tutorials. They are pretty good.
-- Russ
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