One of the biggest questions I encounter from students is how to set their zoom factor on metric drawings in their layout. Since this is major question I am going to get straight to it before doing the other lessons.

The way that I have my classes set up, and I draw is that I have a Template with Layouts that are set up for imperial units (inches), and they always draw full size (Inches, Feet, MM, or Miles) in Model Space. After they draw full size the zoom the viewport to the appropriate zoom factor.

First off there are three ways of setting a Viewport to a specific zoom factor (scale).

- Zoom ___xp while in Model Space
- Use the Viewports toolbar while in Model Space (must be floating or docked horizontally

- Properties of the Viewport while in Paper Space

With Imperial Units you can just type in the scale factor that you want to use; whether it is 1:1 (full), 2:1 (double),1:2 (half), ect. If you are using the Viewports toolbar you can use ratios such as 1:25.4 (full), 2:25.4 (double), .5:25.4 (half), ect but if you are using the Zoom command or Properties the ratios will not work.

In these cases it is easy to turn the ratio into a fraction. To do this you replace the colon with a slash & move the decimal places so that you have whole numbers on both sides.

- 1:25.4 -> 1/25.4 -> 10/254
- 2:25.4 -> 2/25.4 -> 20/254
- .5:254 -> .5/25.4 -> 5/254

So what about other scales such as 3:4? First convert it to a fraction, then convert the fraction to decimal, and put it over 25.4 and complete the process.

- 3:4 -> 3/4 -> .75/25.4 -> 75/2540

What if you don’t want to type the factors every time? In that case you can save them to your computer.

- Type “SCALELISTEDIT” at the command line
- Go to Format -> “Scale List”

Click Add, and fill in your info. I like to name it with a “m” at the end so I know which ones are metric.

After you do this your new scales will show up both in the Toolbar and Properties. I hope this tutorial has helped with your understanding of setting Zoom factors for your viewports. As always remember to lock your viewport after you get the scale set.