Need help figuring scales

[Leif Oh]

Browsing a thread here at Cardmodels.net about Jim Collins' free printable accessories I came across another little gem on his site, namely a calculator for scaling from all sorts of odd scales to other scales.

Now, the beauty of it all was that you could download and save the whole page to disc, and keep it as a stand-alone calculator accessible in your ordinary browser, but you don't have to be on-line to use it!

Having done just that, I couldn't, of course, leave well enough alone, but started fiddling with the excellent little calculator to make it better adapted to the needs of card modelers. The result is a very neat little 16 KB - yes, not MB, and it's only 3.4 KB zipped - calculator. (See the attached images and the zip file below.)

The first image demonstrates a case where you have come across a fact file or a drawing of, for example, an aircraft with the span given as 50 ft, 6 inches, and 3/16 of an inch.

Enter these values into their proper places, press calculate, and you can immediately read it translated into 15,397 mm.

But it gets better:

In the second image, the example is that you wish to know what the span will be in your desired scale of 1:87. Just add that information, press calculate, and you get the result 177.0 mm (after proper rounding). And if you'd rather have the result as 6 inches and 15/16 of an inch, you get that too!

Now, this is useful - having that information immediately at hand you can easily find the scaling factor for any drawing you have downloaded. Just divide your target span measure of 177.0 mm (in this example) with the span measured from your drawing at hand, multiply with 100 and you get the scaling factor in percent to reach 1:87. This last little calculation you will have to perform on an ordinary pocket calculator, though!

You can download the calculator below as a zipped html-file. I have purged a number of odd scales, but if you wish for any particular scale which isn't in there, I'll gladly make a new version. Just write a post here in this thread.

Can I just add that the beauty of this calculator is that it runs in any browser (with basic Java, which means any modern browser), and therefore on any system - PC, Mac, or Linux. And, since you are likely to have your browser running most of the time anyway, there is no need for launching another application - just open a new page in the browser from your file.

And if you create a bookmark/favourite for your saved file, you'll find yourself really swinging, with a drawing from the net in one tab, a factfile in the next, and your calculator in a third, instantaneously available!

Leif

PS. I first developed this calculator over at Kartonbau.de, but put it in a thread there which was for members only. Awaiting a change of venue, I'll just post it here in this thread as well. While purging a number of very odd scales, I have added the two common card model scales of 1:33 and 1:250 (which weren't there in Jim Collins' original calculator).

[SCEtoAux]

Thanks, Leif Oh.
I also saved that calculator from Jim Collin's site to my HD a while back so I could use it off line. I still visit Jim Collin's page, though, because he has a lot of interesting stuff. I even use that calculator on line sometimes too.

Your changes to the calculator sound useful. I will give it a try.
Thanks again.

[Stev0]

Originally Posted by ringmaster

life would be simpler if every PDF included the scale and a reference line; particularly models drawn in non-standard scales.....Chip.

Yep I gotta agree with this 100/1 percent.

[xyberz]

Originally Posted by lunarhighway

hi
scales are not so difficult as it seems.
only i don't know if i can explain it well, my scientiffic english is a little limited...also i'm only used to the metric system, and i mostely build planes...so i'll use those in examples, but that shouldn't be a big problem to convert to whatever you use and build... here we go


for example if something is 1/33 scale it means that the model is 33 times smaller than the real thing so if you want to make a model of an airplane that has a wingspan of lets say 10 meters you devide 10m by 33 -> 0.303030.... so the model is gonna have a span of 30 cm...

now to extrapolate the unknown scale of something:

if you have a model or more common a drawing, but you don't know what scale it is, find an easy distance to measure. On planes this is usually the wingspan... so lets say the drawing has a span of 30cm (A) next you look up the span of the real plane (and preferably use more than one source becouse somethimes there are errors/variations/modifications...wich could end up giving you the wrong end result) let say the real plane was 10m (B)in span.


so now we have to calculate how many times the model or drawing is smaller than the real thing.

to do this simply devide the real size by the scale size A/B or 10m =1000cm/30cm = 33.33333333 so the model is 1/33


if you want to rescale a model...wich i sometimes do. for example you would like to downscale a 1/33 (A)model to 1/72(B)


simply do: (A/B)*100

wich is 33/72 = 0.45833333333 *100 = 45.8333 so you have to scale the original model down 46%

as you see i've rounded the number, wich is extremely very acurate but it doesn't make a visible difference.

if you want to upscale a model just do the same

lets say 1/72 to 1/48

so you do:

(72/48 )*100=150 so you'll have to upscale 150%


anyway i hope this helps you along a bit... i'm by no means a mathematical wizard...(and i hope i didn't write a mistake somewhere )


happy scaling

I just want to reiterate to make sure that I'm completely understanding your calculations correctly.

To scale a model down use the following calculation:

1/60 scaled down to 1/100

60/100 = 0.60 * 100 = 60

So I need to scale my model down by 60% to reach 1/100 from 1/60th scale.

Exact number calculation for people who have to do it manually.

Model piece 1/60th scale size is 100x100 pixels scaled down 60% would then become 40x40 pixels.
100 pixels x 0.60 = 60 pixels - 100 = -40 pixels

Lets do the opposite and scale up.

1/100 scaled up to 1/60

100/60 = 1.67 (Rounded up next hundredth digit) * 100 = 167%

So I need to scale my model up 67% to get from 1/100 to 1/60th scale.

Model piece 1/100 scale size is 100x100 pixels scaled up 67% would then become 167x167 pixels.
100 pixels x 0.67 = 67 pixels + 100 pixels = 167 pixels

I think that's correct right? Please correct my calculations if needed.

No one really posted the exact calculation of each pixel in case they had to resize the pieces to fit onto the page, just the main percentages.
The only problem I saw with that is if for instance, the model was a PDF and you wanted to scale up. If you were to scale up a PDF to a considerable amount, your pieces would run off the page and you wouldn't be able to print it out. So your only option then would be to cut and paste the newly resized pieces onto another document or picture format in order for it to fit onto a page to print.

[cgutzmer]

Would it be possible to get this calculator to tell you the percent that you need to print at to change from one scale to the other? This would assume you know the current scale already and the scale you want to go to. Now that would be perfect for me I always think I understand it until someone tries to explain it
Chris

[SCEtoAux]

Chris, just move the decimal two places to the right to get the per cent.

In the above example to reduce from 1/60 to 1/100 you divide 60 by 100 and get .6 as the answer. Move the decimal two places to the right and you get 60%. You would print the original pieces at 60% of their current size to get the smaller size model.

To enlarge from 1/100 to 1/60 you divide 100 by 60 and get 1.67 (rounded to two places). Move the decimal two places to the right and get 167%. You would print the original pieces at 167% to get the larger size model.

That works for any scale conversion. 1/32 to 1/76 would be 32/76 or .42 or 42% reduction. 1/76 to 1/32 would be 76/32 or 2.38 or 238% enlargement.

1/300 to 1/700 would be 300/700 or .43 or 43%. 1/700 to 1/300 would be 700/300 or 2.33 or 233% etc..

[cgutzmer]

Well hey that makes sense. Thanks Being the lazy bum I am I would still like a calculator though
Chris

[Toddlea]

This is the easiest tool I've used to compute scale.

[xyberz]

Originally Posted by SCEtoAux

To enlarge from 1/100 to 1/60 you divide 100 by 60 and get 1.67 (rounded to two places). Move the decimal two places to the right and get 167%. You would print the original pieces at 167% to get the larger size model.

The only problem I see with upscaling is when you say to increase the model size 167%. For someone who is in a rush and isn't paying attention at the moment, might accidently increase overall size by 267% instead of 167%. I guess the brain seems to work that way sometimes when we don't mind our work. They'd think to increase size by 100%, in turn doubling it and increasing it another 67%.

I think it'd be much easier if we said to increase your model size an additional 67% to reach 1/60th scale from 1/100 scale. It would be much harder to mistaken a phrase such as that, well at least in my belief.

[xyberz]

Originally Posted by Toddlea

This is the easiest tool I've used to compute scale.

Thanks for the scaling tool. It would be incredibly fantastic if it had a function to calculate pixels, since chances are that you're getting your paper model on the computer. I think it would be much more accurate in the computer world than using standard measurement scales.

If you really think about it, a pixel is incredibly small in size so calculations using pixels would result in very precise measurements whether upscaling or downscaling.