The Society of American Period Furniture Makers

Books, Plans, Magazines and other media => Discuss plans and drawings. => Topic started by: rchampagne on May 08, 2010, 11:36:35 AM

Title: Scaling photos with Sketchup?
Post by: rchampagne on May 08, 2010, 11:36:35 AM
Probably like most of us, I've spent a lot of time scaling photos by hand and have been somewhat frustrated with the amount of time/effort that I put into this.  Usually the pictures I find of pieces I'd like to build are relatively small and low resolution.  I end up enlarging the photo to a scalable size and then working from fuzzy lines.  I figured there must be an easier way to do it, so I downloaded Sketchup.  After spending a few hours on a picture of a highboy, I am wondering if the old fashioned way might not be more time effective for me.  I am not really looking for a full 3D model of the piece.  I would just like to pull some dimensions from the picture and go from there.  Any preferred methods I should try out?  I have some drafting experience (all by hand), and minimal CAD knowledge, so the Sketchup is pretty new to me.  Does anyone use it for scaling photos?
Rob
Title: Re: Scaling photos with Sketchup?
Post by: Antiquity Period Designs, Ltd. on May 08, 2010, 11:43:05 AM
Rob,

I use the simply method of scaling the photo, no Sketchup or CAD.  I don't know how to use Sketup or CAD and the scaling method I find to be much faster than spending hours at a computer especially if you want only a few dimensions.  I do find it easier to use a dial veneer calipers to scale the photos.

Dennis Bork
Antiquity Period Designs, Ltd.
Title: Re: Scaling photos with Sketchup?
Post by: rcortright on May 08, 2010, 02:10:25 PM
There is a program called (I believe) "Resize It" May help1
Title: Re: Scaling photos with Sketchup?
Post by: rchampagne on May 09, 2010, 08:13:23 AM
Dennis and rcortright, thanks for the replies. 

I was hoping there would be a magical program that would allow me to enlarge or reduce a photo to a useable size (ie scalable size) then use the mouse to take measurements.  So far I haven't found it.  Maybe we should look into developing something like this.  I bet we'd get rich by selling it to the mass period furniture making market. 
Rob
Title: Re: Scaling photos with Sketchup?
Post by: klkirkman on May 09, 2010, 11:18:09 AM
Rob,

It does not work quite like that.

If you want to offer accurate dimensions, the software needs to know the exact location of the camera relative to the piece, and you need optical information about the lens. Software I have used in the past worked best when there was a test shot of a grid at the same distance away as the object available to calibrate the system.

Your eye may not see it, but the plane image you are scaling from has many types of distortion. Without recognizing and correcting, the accuracy of your product is suspect

Having said that, how about some simple mechanical drafting devices: the Gerber Scale, or proportional dividers ?


Karl
Title: Re: Scaling photos with Sketchup?
Post by: ttalma on May 11, 2010, 07:37:23 AM
Rob, Actually sketchup is that magic program you are looking for. It has a process for matching photos to align the drawing axis with the photograph. Once the drawing axis is aligned. you can take accurate measurments right off the drawing (the one thing it can't do is make the picture sharper).

I use this quite often, and can start taking measurements within 10 minutes. It takes about an hour to learn the process but once you have it down it's real easy to do. I suggest you take a look at Dave Richards Blog, design, click, build (start from the first post and you'll be a sketchup master http://www.finewoodworking.com/blog/design-click-build)

Here is a link to sketchups instructions for photo matching, http://sketchup.google.com/support/bin/answer.py?hl=en&answer=57655.
Title: Re: Scaling photos with Sketchup?
Post by: rchampagne on May 11, 2010, 10:08:35 AM
I played around in sketchup for a while and imported a photo of a highboy I'm interested in making.  I alligned the perspective bars, etc, though had some difficulty setting the correct scale.  The highboy is 86" tall, so I tried to use a 12" scale.  86/12 = 7.16, so it was hard to eyeball .16 of a scale line.  Do you scale it roughly, take a test measurement of a known dimension, then fine tune the scale?  Also, do you have to trace the whole piece before taking measurements?  Like I said, I don't need to model the entire piece, just want to be able to pull important dimensions off it.  From the time I've spent on it, it seemed to be a very useful program, I'm just not quite at the point in the learning curve I need to be to make it work for me.