Friday, February 06, 2009

Precision in Illustrator

Sue wrote and asked:

"I’m setting up documents in Illustrator CS4 and when I set the page to a size with more than three decimals it rounds it up to two decimals (Example 2.125 rounds up to 2.13). Is there any way it can be changed?"

When working with the inches measurement system Illustrator appears to "round up" when you enter three-decimal precision in the Artboard width and height fields. However, for some reason known only to the programmers at Adobe, this is done for on-screen display only. The 3 (or even 4) decimal precision that you enter is retained. So if you enter 2.125" for the page width, the page will be 2.125" wide.

You can verify this by choosing Window > Document Info, and choosing Document from the Document Info panel menu. You will see the exact dimension that you entered for the Artboard width and height listed here.

(This applies to Illustrator CS3 and CS4, and if I recall correctly, previous versions as well. I don't have an older version handy to test.)


Anonymous said...

If this is indeed true, then why when I create a 'box' using the three decimal points and place it on my two decimal point rounded artboard is it smaller?

And since when are designers so 'dumb' as to not be able to understand three decimal points that you need to round up for us?

Keith Gilbert said...

@Anonymous: I don't understand what you are asking. Can you explain in a little more detail?

Kimball Clark said...

Regarding this issue, this page contained the best answers I have found on the web This is an issue Adobe can't seem to acknowledge or give any profound direct answer, as shown in their Forum.

Eirdesceoil said...

I tried a box measuring 5.1875 x 4.234375 (inches)and Illustrator rounded up on the fourth digit. I copied and pasted into Freehand and the box measured the exact measurements. You can see all decimal places in Freehand, but only 4 decimal places in Illustrator.

Jeff said...

I believe you are wrong about rounding up in CS3.

I am working in CS4, the rest of the Designers here are in CS3.

While using CS4, I have tried to add to my document size using the + sign in the artboard, adding 7.0625 either making it 2 wide or 3 wide. When I add it in CS4 14.13 and it should be 14.125. So when I add it once more the total length is off by that much x2.

But we just did it in CS3 and it held the correct number of digits whether it was 3 for 4 past the decimal point. And we got the dimensions in the end we needed.

So there is a stupid problem in CS4 that should not be there.

It was never a problem in the older versions either. Now I can not tell you if 88 even had the ability to add up in the dimension boxes or not since that was way back in 1989/90, but I would say within the last 10 years it has not been a problem.

quinne Fokes said...


Thank you for this. I'm using Illustrator CS5-- and it still is unable to give the precise measurement--rounds up to 2 decimal points.

Glad the correct info is actually "there" in thefile. . . .but, I'm still having a related (possibly problem) and the tech fellow at Adobe couldn't tell me how to fix it.

I needed to move the edge of an illustration by 3 or 4 decimal points, and was unable to do ti. The image or edge in question kept snapping back-- and I'd turned off all of the snap to and related options.

Help. (a fellow designer had the same problem in CS3)

fyi- we're both on Macs.

pedro said...

"The distance the object moves each time you press an arrow key is determined by the Keyboard Increment preference. The default distance is 1 point (1/72 of an inch, or .3528 millimeter). To change the Keyboard Increment preference, choose Edit > Preferences > General (Windows) or Illustrator > Preferences > General (Mac OS)."

Nicolás Montecchiari said...

quinne Fokes I had the same problem in moving objects in illustrator cs5. Also had the problem of not being able to determine an exact size for some objects (I work in milimeters). I fixed ir doing the following: go to the transform object window, click the options button in the upper right corner, and then deselect the option "align new objects to pixel grid" then click on the object. At this point, in the transform window should appear the "align to pixel grid" option, uncheck it. Voilá! Hope it was helpful. cheers mates!