Replies

1. 
   Steinmetz | Aug 25, 2005 11:48pm | #1

   Brent,
   Take the pic with a digital camera,
   then upload the photo onto your computer
   (Save in 'My photos'. Download the photo,open, zoom in to roughly fill the screen, then print it on graph paper.

   (Graph paper comes in 1/4"-1/2"or,1" squares.) From the resultant composite print, you can deduce all the measurements by simply appling a known chair seat height dimension and extrapolate from there . Ed

   
   

   ---

   Edited 8/25/2005 4:54 pm ET by Steinmetz

1. 
   BrentS | Aug 26, 2005 12:36am | #3

   Thanks for the info guys.

   Ed, the picture I'm using is in a magazine and was taken at an angle. The left hand table leg is 3 3/4"  while the right one is 3". While your idea would work with a straight forward shot, in this case it won't. The article I am refering to uses angles and straight planes to extrapolate the measurements from a photo like the one I am talking about.

    

   Butch, thanks for the info. I'm going to have to go over the magazines more carefully again to find what must have been in front of my face last time I looked.

    

   Brent

2. 
   PlaneWood | Aug 26, 2005 12:42am | #4

   If you want to be precise though, I have found out that most printers will print in the "X" direction and in the "Y" direction at a slightly different scale.  I found this out when taking pics of plane handles to generate patterns.  Every image had to be tweeked in the X or Y direction to get the prints to come out correct.  At least it was this way for the 3 different HP printers I tried.

   Also, if the object is at an angle to the camera, you have to use trig to take that into account.

   PlaneWood by Mike_in_Katy (maker of fine sawdust!)PlaneWood

1. 
   Steinmetz | Aug 26, 2005 04:45am | #10

   PW, Never thought about that X-Y inconsistency one could make two prints one with portrait configuration and the other rotated 90 deg's?I recall an article in Popular Mechanics, where if you cut the drawing out of the magazine and soaked the newsprint paper in paraffin oil, then cut and fit in a 35mm slide frame and project it on the wall/sheet/screen/or white paper, you could trace the outlines with a pencil to make an enlarged copy to whatever scale you needed?

2. 
   butchf18a | Aug 26, 2005 12:16am | #2

   it was in FWW in the last year. don't have the issue # handy, but if you have kept your past issues (doesn't everybody?) you should be able to find it.

    

   butch

3. 
   stantheman | Aug 26, 2005 01:07am | #5

   BrentS

   I believe there is such an article in the current WOOD magazine.  I know I saw it this week.

4. 
   dukeone | Aug 26, 2005 01:24am | #6

   FWW issue#170 ''Scaling from Photos''

   KDM

   Kenneth Duke Masters
   The Bill of Rights
   December 15 1791
   NRA Endowment Member
   LEAA Life Member
   CRPA Member
1. 
   BrentS | Aug 26, 2005 02:05am | #8

   Thanks Duke.......that saves me a bit of time.

    

   Brent

5. 
   MarkRD | Aug 26, 2005 02:05am | #7

   Here's a technique I've tried with good success of course it helps when the picture of the furniture is straight on....

   I did this with a "stickly" catalog.

   They show a picture and publish dimensions.

   Let's imagine that the unit was 30" high according to the caption.

   Measure the height of the unit in the photo. Perhaps it's 4.5" tall.

   Now you have a scaling ratio - 4.5/30 = 0.15. Check this ratio with other given dimensions (width, depth etc.) It should be pretty close.

   Now measure some non-given dimension on the photo (the height of a drawer for example) then use the .15 to convert. So if the drawer measured 0.5" on the photo, divide 0.5 by the conversion factor of 0.15. 0.5/.15 = 3.3" Voila. Your drawer should be 3.3" tall.

   Do a bunch of dimensions and make some full scale drawings to test your conversions.

   You'll need a precise ruler to measure the photos...

   HTH,
   Mark

   Visit my woodworking blog Dust Maker
1. 
   BrentS | Aug 26, 2005 02:07am | #9

   Stan and Mark,

    

    Thanks for the info

    

   Brent

6. 
   mudman | Aug 26, 2005 05:10am | #11

   I remember that article and though it was interesting. I think that the process is called deminishing lines, or something like that. Have to evtent all the lines to their convergence point and then you can get acurate measurements. As you said the simple "find the scale with a ruler trick" won't give correct measurements if the picture is taken at an angle, especially from a corner as most are. The width will be very off.

   MIke

1. 
   MarkRD | Aug 26, 2005 05:36pm | #12

   You can compensate for the vanishing point effect... Provided you have dimensions. Using this pic, try an experiment. The table top is 11.75" wide, the length is 72" height is 32" floor to top of top.I believe you have everything you need to compensate for the z dimension (into the paper)If you'd like to experiment, Tell me the size of the legs etc using the method I described above and the picture posted here.BTW I used the Photoshop filter "Stylize, Find Edges" to create the sketched look and I removed all the color information. It makes the photo a bit easier to measure.MarkVisit my woodworking blog Dust Maker

   
1. 
   WillGeorge | Aug 28, 2005 07:52pm | #13

   I like Marks theory! I have use something like it for pictures I got from China of REALLY OLD furniture... It works..Well, depends on if you need EXACT dimensions.. I hardly think it is necessary to be THAT exact.. The ratios of sizes mean the most...Just me...If you need EXACT you need a X/Y/Z scale layin' out in the sand like in the Mars Rover pictures...

   Edited 8/28/2005 12:54 pm ET by WillGeorge