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Question

Measurement precision FAIL

Forum|Forum|6 years ago
July 10, 2019
2 replies
4851 views

Hi,

I'm having troubles to make precise patterns because Illustrator keeps changing the measurement of my object.

Actually I'm having problems with patterns because white lines appears (but that's another issue...) so in order to fix that I read that it was needed to make forms with rounded figures. So I made a 20x20 mm square with the form of my pattern. See below.

(I selected them so you can see the difference) I first tried with a 20x20mm mask (the one on the left) but the white lines kept appearing. So I decided to trim it (the one on the right) but what surprised me –and here comes the issue I'm asking help for– is that illustrator changes from a 20x20 mm square to a 20,03x20,02 mm square for a reason I can't understand. See below.

And that's very anoying. It's not the first time that I have this kind of issue.

Does anybody know why this happens?

Thanks a lot

This topic has been closed for replies.

Ton Frederiks

Community Expert

tomasg33705904 wrote
Actually I'm having problems with patterns because white lines appears (but that's another issue...) so in order to fix that I read that it was needed to make forms with rounded figures. So I made a 20x20 mm square with the form of my pattern.

The rounded figures should be point or pixel values.

When exporting as an image, fractional pixels get rounded (anti-aliased) as whole pixels, and can give you extra unwanted pixels.

Your example of 20mm leads to these extra pixel: 20mm = 56,693 px

tomasg33705904Author

Participating Frequently

Great! Thanks for this answer! I think this will solve the white lines problem.

But what about the arbitrary measure increase?

Thank you

tomasg33705904Author

Participating Frequently

How do you export?

A single pattern tile, a rectangle fillled with the pattern, a selection, an artboard?

Do you export at 72 ppi or something else? What anti-aliasing is used, art or type optimized?

Ooook looks like the type optimized anti-aliasing was the problem.

I'm exporting an artboard with a rectangle filled with the pattern. When I activate the art optimized anti-aliasing the lines disappear. I think this solves it!

I have another question. This art optimized anti-aliasing only has an effect on the diagonal pattern. On the pattern I showed you in the original post the art or type anti-aliasing doesn't seem to affect at all. I mean, the other pattern looks just fine with both ant-aliasing. Is this because the diagonal pattern is one of the most difficult to get right as you said before?

Thanks a lot!

Monika Gause

Community Expert

The white lines are preview issues. Most likely they don't exist.

Try and turn off Antialiasing in the Genereal preferences. If the lines are gone, you're good.

tomasg33705904Author

Participating Frequently

I don't think that's the issue because when I export a JPEG they are still visible.

Thank you for your answer anyway!

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