Topic: Custom Scale...

[Qwest]

A little while ago, i made a post here about creating a ruler in ACAD...

I got all the help i needed, and progressed to created a ACAD file showing 4 different scales... these scales would be adjusted to the scale i would as & when etc... I done this by going into the properties of the viewport in my Layout, and adjusting the number in the "Custom Scale" box...

Now it came to me actually using the said ruler today on a drawing (was originally A1 sized, but got e-mailed to me, and printed in A3!...  So it came to usin the ruler, i tested it and it was wrong...

i went back to AutoCAD, and realised that the "Custom Scale" property was a little more complex that i first thought!

I assumed that you put in 0.150 for example to get a scale of 1:150 but this appear's to be wrong...

I've worked out that if you put in "0.200" in the custom scale box, and print the said ruler out on A4 paper, it shows a scale of 1:500!  If i put in "0.50" in the custom scale box, i get a scale of 1:200..

So how does this "Custom Scale" work?!... what would i need to enter in the box to get a scale of 1:70 or 1:150 for example!

[ML]

Well, whenever you are figuring out scales mathematically, it is times 12 units

For example: If you are doing 1/4"=1' then your scale factor is 4 X12 = 48. This is because there are 12" in a foot

Likewise, if you are doing 1:50, then simply times 50 X 12 = 600
600 is your scale factor

Hope this helps

Mark

[Dent Cermak]

but he's metric

[MikePerry]

Hi

Give the following Excel file a look over, hopefully it will help with Metric Floating Viewport Scales + Text Heights -

http://www.theswamp.org/lilly_pond/mikeperry/ViewportScalesTextHeights.xls?nossi=1

Have a good one, Mike

[Qwest]

Thank's guys!... i will try and work it out from here...

[SMadsen]

I assumed that you put in 0.150 for example to get a scale of 1:150 but this appear's to be wrong...

I've worked out that if you put in "0.200" in the custom scale box, and print the said ruler out on A4 paper, it shows a scale of 1:500!  If i put in "0.50" in the custom scale box, i get a scale of 1:200..

So how does this "Custom Scale" work?!... what would i need to enter in the box to get a scale of 1:70 or 1:150 for example!

It's only as complicated as you make it. A scale factor of 1:200 just means that something is drawn 200 times smaller than what it's supposed to be. Said in other words, if 1 unit represents 1000 millimeters in real life then it will be shown as 1000/200 = 5 mm on paper. Look at the colon as a division sign .. 1:200 is equal to 1/200 = 0.005.

Apparantly your drawing has already been scaled from model space to a viewport in paper space. Seeing that a custom scale of 0.5 will give you an output in 1:200, it means that your viewport is set to a scale of 0.005/0.5 = 0.01 = 1:100.

To get your final custom scale value, take your desired output scale and divide it by  the viewport scale (just list the viewport and look for a number followed by "xp"):

custom_scale = output_scale / viewport_scale

For example,
viewport_scale is 1:100 = 0.01
output_scale is 1:200 = 0.005

custom_scale = 0.005/0.01 = 0.5 = 1:2


Or, for a desired output of 1:70
viewport_scale is 1:100 = 0.01
output_scale is 1:70 = 0.14285...

custom_scale = 1/70/0.01 = 1.42857... or simply 1:70*0.01 = 1:0.7