Need help figuring scales

[thewoodengraver]

I realize I need to know the size of the subject to figure out the scale of the model. But that's all I know about scales. What is the mathematical formula?
Any suggestions on tutorials via websites or software or formulae will be greatly appreciated. Thanx

[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

[Ashrunner]

I once found several program for calculating scale. Send me a PM with an email address and I will email you one I use most often.

However, if you prefer, you can use several online calculators. This one allows both up and down scaling.

http://users2.ev1.net/~jimbobwan/scalcalc.htm

[lizzienewell]

Measure something on the model that you know the size of in full size. Human figures, doors, or height of building stories are a good thing to look at. If a drawing of a model lacks anything that you know the size of then draw a person next to drawing adjust the size of the person until it looks right and figure the scale from the person.

I will figure out the scale of my model because I haven't done it yet. I've got a human figure in it that is .41 inches I know that an average adult is 5'8" and an average sized adult man is 5'10", woman 5'6" so I convert both to the same units. I might be slightly off on these numbers but it's all approximate anyway. You might be most comfortable with a photo or drawing of yourself for scale and then use your own height.


My average adult is 68 inches. I can handle scale several ways. I can divide the smaller number by the bigger .41/68 = .0060 This is useful for multiply the original size of the part to produce the size of the model part. If I want it as a percentage I move the decimal point two places .60 %. In coreldraw I can use this to change scale of parts.
For a more tradition scale measurement, I divide the larger number by the smaller 68/.41= 1:166. I find the ratio expressed as a decimal or percentage to be the most useful. I hope I got my math right.

On a related note, I like models to include human figures or indications of human figures such as doors and chairs. This gives scale to the viewers and allow them imagine themselves on the same scale as the model.

Lizzie

[wunwinglow]

I prefer to work in meters, or milimeters. I grew up with inches, and fractions of inches, and feet, and yards, and furlongs, and chains, and groats, and ells, and bushels, and stones, and hundredweights (which had 112 pounds in them, go figure...) And the concept of a metric inch; OOOO, my brain hurts!

Thank you Napoleon Boneparte, for the metric system. Even if you did get the distance from the North Pole to Paris wrong.....

Tim P

[lizzienewell]

For scale the unit of measurement doesn't mater as long as you use it consistently. A chemistry teacher told me to always mark unit of measurement when doing calculations. In ratios the units cancel out so if you mark them and accidently mixing meters and inchs you will notice because the units won't cancel.

[ShipWreak]

Heres a little consistancy as far as I understand it....

Say you want to scale something to 1:24 in inches.

100 x 12 in.
----------- = 1:24 scale
50


Hope that was correct ;-P

Ship

[RINGMASTER]

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

[thewoodengraver]

Thanx all,

All the information submitted helped me understand scales and it looks like I lucked out!, ashrunner (poobah) hooked me up with a friggin piece of software that takes the guesswork (and brainwork) out! (see his post for link) Now I don't have to go into the wayback machine to remember Math!!!

[SCEtoAux]

Here is another calculator that you can download. It is a small file, easy to use, with a few different conversions.
Scale Calculator

[hpept]

i completely agree with ringmaster. All would be simpler, and people could immediately measure the graduated strip to see if the printer does its work right. Sometimes during printing little adjustments are made to fit the page, and it can lead to a model in a wrong scale.

[SteveM]

Originally Posted by wunwinglow

...And the concept of a metric inch; OOOO, my brain hurts!
Tim P

I work in the disk-drive industry and for a long time the height the read/write head flew above the disk was measured in micro-inches. We've since migrated to using nano-meters partly as a general trend to the metric system but also because we now fly in the range of just a few nm! Most of our test equipment still measures in microinches, though so the magic numbers of 25.4 and 39.37 get used quite extensively 'round here.

Steve

[Ashrunner]

Originally Posted by SCEtoAux

Here is another calculator that you can download. It is a small file, easy to use, with a few different conversions.
Scale Calculator

Thanks SCEtoAux...this is the calculator I sent Woodengraver. I spent quite a while looking for a link to the file and only found dead links for it and one other freeware scaling software product I have.

At least now, others who want the program can get it 8v)

[jleslie48]

I wrote up my notes from my lecture to 7-8th graders on scale as a faq that I think does a pretty decent job of explaining how scale work:

http://www.lhvcc.com/egiftshop/faq.html


see if if makes any sense to you.

also, If you are so inclined to use excel, I wrote a fairly intricate yet easy to use spreadsheet that helps you document an item (ship,plane, rocket, etc)
and allow you log all the 1:1 measurments, and then compare them side by side to any two scales you like (1:48, 1:96, 1:1) in any unit of measure. I redo this spreadsheet for each item I make design a model for so I can reference the numbers later, and check scale. Here is an example of my Saturn V spreadsheet:

http://lhvcc.com/egiftshop/cone/scaledown02_satv.xls

with a bunch of the measurements I needed to make the model. I hope it is self-explanitory, but if its not feel free to ask a question or three.

[Kaz]

I found another one, after running to a plastic convention, (Bought myself a nice little Rata, and won a 109e in a raffle)
http://www.mksmc.co.uk/hintsandtips/...calculator.htm