August 26th, 2009 by Jeff Hipp

Adobe Illustrator Math Bug

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Senior Designer, Jeffry Hipp, talks about using the duplicate function in Adobe Illustrator - and a long-time bug that you need to be aware of.

Filed under Creativity, Tips, Tricks & Hints

 

One great thing in Adobe Illustrator is the ability to duplicate and move an object - then repeat that action as many times as you need. This is a handy tip, but also a "be aware of a problem".

I love a lot of Adobe products, Photoshop and Illustrator are cutting-edge software that no Designer can do without. However, there is a bug in Illustrator that has been on the top of my list of "things that piss me off" for years. It's a bug in their duplicate function - and has been there since they "joined forces" with Aldus around version 5 in 1994 or '95 (we're now on v.14.0.0 with Adobe CS4 btw)!

Here's the issue, try it yourself with this simple test so that you know: Open a new Illustrator document, turn on your rulers and place vertical guides every 1/2 inch. Draw a square that is 1/4 inch and place the right edge corner points precisely onto the first left guide. Grab & duplicate the square (holding the option & shift keys - click & drag the object to the right) being sure that you have grabbed the points so that your move is exactly 1/2 inch with the points ending on the next guide same as with the first square.

With the second square still highlighted or active, now duplicate the action (Command key & D key) and it should duplicate a new square to the next guide, repeat several times. This should always put the square exactly 1/2 inch apart - but it doesn't. After 18 steps it's off by .092" or 3/32"! Frustrating? You bet! Imagine if you have some sort of intricate pattern that you need to make using a shape - and that pattern needs to fill a certain width - it ends in the wrong place! I haven't come up with any real solution or quick fix to this problem, so I wanted you to be aware of it too. If you do have a fix, please share.

Note: I am. however, VERY GLAD to see that Adobe Illustrator appears to have very recently fixed a long-time problem with rounding-up decimals. I still had this problem in Mid May, but can't replicate it now. Here's what it was doing - Say you needed a square that was 2 1/8 inches - you'd enter 2.125, but Illustrator would round it up to 2.13. This doesn't fly when you need to be accurate in your artwork - like when creating a die-cut for a print piece or a vector shape for metal fabrication, etc.

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