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asee23455
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curious issue with extrude and rotate

May 17, 2013 11:24 AM

Tags: #illustrator #cs6 #rotate #confusing #extrude #odd #nonintuitive

I've found a curious issue with extrude and rotate in CS6. It's not a bug, but it is a nonintuitive behavior that is confusing, and sometime troublesome. I think this is something that ought to go on the to-do list for the devs. Anybody else agree? Disagree?

 

Example:

 

Rotate_issue.jpg

 

I began with an arrow-shaped path, to which I applied the "extrude" effect. I then put an icon on top of the arrow, and grouped the icon and arrow. Now, I'm using this icon-arrow in several different parts of my design, in different orientations. As I rotate the arrow, the relative position of the icon and the arrow appears to shift. I believe this is happening because, as you rotate the icon-arrow, Illustrator rotates both the icon and the arrow about the center of the bottom face of the arrow. This is because the top face of the arrow is essentially fictitious, just an artifact of the extrude effect. So, even though the icon appears as if it is drawn on the top face of the arrow, it behaves as if it is attached to the bottom face of the arrow. When you apply a transform, that transform affects the bottom face of the arrow, causing the top face to shift relative to the icon.

 

The solution would be to add an extra check box to the extrude effect, asking whether you wanted to extrude upwards (the way things are currently done) or downwards. If you could extrude downwards, then the top face of the arrow would be the "real" face, the one affected by transformations. You could then put an image on the top face, group the arrow and the image, and when you applied a transform, the icon would remain fixed relative to the top face, which would meet your intuitive expectations.

 

If anyone is curious to experiment with this particular example, I've posted this file to Google docs here:

https://docs.google.com/file/d/0B0Hoxcl5zTEtTXo5QnNsMGwwOGc/edit?usp=s haring

 
Replies
  • Currently Being Moderated
    May 17, 2013 11:50 AM   in reply to asee23455

    agree that would make it easier, but easier is not the illustrator way.

     

    so what you could do is place your acorn on the plan where you want it to be and apply a transform effect to move it up to the extruded face. so now when you rotate your group, the acorn rotates along in relation to the  original face and then moves up to where it should be.

     
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    May 18, 2013 12:46 AM   in reply to asee23455

    but it does work because i downloaded your file and i did jsut that. it isn't exact, but your suggestion on how to fix it wouldn't fix it anyway. the reason the acorn doesn't match is because of the distortion from the perspective not the direction of the extrusion. even if you could dictate the extrusion to go downward, the arrow would still rotate into perspective (distort) and then extrude. to avoid that, what you want is to extrude in axonometric and to do that you make your perspective rotation angle 1 degree, then make your extrusion length a lot longer to match what you want. with 1 degree there will be minimal distortion to the arrow as you rotate it and the acron will match.

     

    i uploaded your file with your orignal 10 degree angle, and you'll see that they stay in sync pretty well. i drew a box around the acorn to better distinguish the difference. then i recreated the same thing with a 1 degree angle and on that version it stays in sync almost perfectly.

     

    again. it doesn't matter wich direction you extrude since in perspective both faces will be distorted. if you want to keep the distortion from the perspective, you can apply the same perspective rotation to the acorn without the extrusion and it will distort in the same way as the arrow. i added that option to your file. they are all group and you can rotate them and see that they stay together pretty well, except the first one is a little off.

     

    i uploaded your file with my solution

     

    https://docs.google.com/file/d/0B4ilRoSBagc3WDY3MUR1bDNpV0E/edit

     
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    May 18, 2013 11:10 AM   in reply to asee23455

    it is pretty much what you have you just need to move the image up with a transform effect to match the extrusion.

     

    so basically, you apply a 3d rotation effect to your image to match the rotation of your arrow, then you apply a transform move in the vertical axis to match the height of your extrusion.

     

    hope this helps

     

    https://docs.google.com/file/d/0B4ilRoSBagc3d2w2Ylc2cWxFVjA/edit

     

     

    if you want to get real anal about it, we are only matching the rotation of the arrow at the center of the extrusion, if we wanted to distort the image perfectly, the rotation would have to be slighty higher, but it is hardly noticable anyway.

     
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