Photoshop/autocad

Model Railroader General Discussion (Model Railroader)
1

Has anyone ever used Photoshop CS3 or Autocad to resize a scale drawing from say 1/4"=1’ to HO scale 1/87.1? Is it difficult to do?

I have access to both programs, as well as a digital copy of the scale drawing from which I intend to scratchbuild. I can do it by hand, but I thought I might be able to save myself some time and use one of the aforementioned programs.

Thanks in advance

2

I have done scale changing with AutoCad before. If you have the digital original Autocad file it ought to be a piece of cake. I did not change to 1/87, but it should be the same thing except you may have to move/resize some legends or use a magnifying glass. I was not aware Photoshop had an engineering drawing program out there.

3

Photoshop has a crop and resize function.

You’d have to do the math to figure how long the overall drawing should be in 1/87 vs. 1/48.

A copier would generally be easier. Blueprint shops often have large format copiers if the original drawing is bigger than 11x17

Eric

4

rgappel,

Its been a while since I’ve used AutoCAD. You should be able to do what you are talking about by going into Options and changing Units to the scale you want. Options would be at the bottom of one of the pull down menus of your Tool bar.

If you just want to see what it would look like printed out, you could scale it in your printer options, although you might not get the “exactness” that you want.

Tom

5

Photoshop can easily change the SIZE of an image to any scale you like, but unless you are making actual size prints I don’t understand what you want it to do. 1/4"=1’ is 1/48 Open the file in Photoshop. Save it with a new name so you won’t damage the original file.Then, Image Size, make sure retain proportions and resample are on, in either dimension multiply the number of pixels by 48 then divide that number by 87 and hit enter. Then print it.

Perhaps what you really want to do is use a new layer to overlay a grid. Then by resizing the grid you can simulate different scales. You can resize numerically using the “transform” function.

Other than that you probably want to use a CAD program.

6

Thanks for all the input.

What I wanted was a scale drawing that I could use as a template for scratchbuilding. Sounds like CAD is the way to go if the original is already in CAD. I have a tiff. (like jpeg) of the original blue print, so I will have to see if that will work in CAD.

The print options might work as well. I could reduce it to ~55% of the original (48/87) and most likely get good results. Luckily for me I have access to free, large printing, maybe even a plotter. I think 11*17 should do the trick though.

Tuition dollars at work, right?[(-D]

7

I tried to use photoshop to make the image 55.17% of it’s actual size(48/87). I was able to scale it down, but it was still a little bigger than 11*17 so I cut the image into chunks and tried to print sections off with the intent to splice them all together later. The problem I ran into was that the image still came out of the printer larger than HO scale. It is definately smaller than the original image, but not quite small enough for HO.

Is it possible that the printer scaled the image back up to fit the entire page? If so, how can a prevent that from happening? I have the image to the size I want, so I want the printer to print the image at 100%, but not fit it to the page.

The wierd thing is that the cropped sections are still larger than the print window, so I don’t understand why the printer would make the image larger still. If anything I could see the printer reducing the image to something smaller than HO so as to fit the entire image on one page.

8

Rgappel,

I’ve had good success using Microsoft Word to produce accurately-scaled prints of measured drawings and orthorectified photos. Here’s how to do it:

    1. Open and save a new Word document. If your image is wider than it is tall, chose “Landscape” from the “Page Setup” menu.
    1. Also in the “Page Setup” menu, chose the size of paper you will need to print on (in your case it sounds like 11" x 17").
    1. Insert your image on a blank page using the “Insert Picture” command on the “Insert” menu.
    1. Drag a corner of the image to make it roughly the size you think in should be at the scale you want to print it.
    1. Print a test image.
    1. Measure a known dimension on the image with your scale rule.
    1. Divide the value of the known dimension by the value you measured with your scale rule. EXAMPLE: If the known value between to points is 47.5" and you measured 42.9" between those marks with your scale, 47.5" / 42.9" = 1.11.
    1. Go back to your Word document and right-click on the image.
    1. Chose “Size” in the pop up menu.
    1. Make sure the “Lock Aspect Ratio” box is checked.
    1. Use your calculator to multiply the number you calculated above by the value shown in the “Height” box in the pop up menu. EXAMPLE: 1.11 x 5.47" = 6.07"
    1. Change the value in the “Height” box to the new value you just calculated (6.07" in the case of our example).
    1. Print you image again.
    1. Check the known dimension with your scale rule. It should be spot on.

Good luck!

Charlie

9

I’ll have to try that, thanks.