6 Replies Latest reply: May 18, 2013 8:00 PM by asee23455 RSS

    curious issue with extrude and rotate

    asee23455 Community Member

      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=sharing

        • 1. Re: curious issue with extrude and rotate
          mec_os Community Member

          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.

          • 2. Re: curious issue with extrude and rotate
            asee23455 Community Member

            I appreciate the thought, but I don't think that works. In my example, I pretty much did as you suggested. I drew the arrow, then put it where I wanted it to be, up on the extruded face. And indeed, when I rotate the group, the acorn does rotate with the original (bottom) face of the arrow.

             

            The problem is that, as you rotate the arrow, the changing perspective causes the original face and the extruded face to move in different ways. So although the acorn moves with the original face, it doesn't move with the extruded face. In fact, it cannot move with the extruded face. Since the two faces of the arrow move in different ways, the acorn can only move with one of them, and the coding in Illustrator dictates that the acorn move with the bottom/original face.

            • 3. Re: curious issue with extrude and rotate
              mec_os Community Member

              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

              • 4. Re: curious issue with extrude and rotate
                asee23455 Community Member

                What you've got looks good. As you say, they stay together pretty well, but I don't understand what you've done. I see how you've changed the settings on the extrude/bevel effect (1 degree, 200 pt). But I don't understand what you've done to the acorn/strawberry. Some of them have a translation-type transform, and some also have a 3D rotation type transform.

                 

                I revised my example, putting an extrude on the arrow, and a 3D rotate effect on the acorn, using the same settings for both. But whether I use a 10 degree perspective or a 1 degree perspective, I don't get the effect that you have. So I'm missing something.

                 

                new file here: (not that it does much good)

                https://docs.google.com/file/d/0B0Hoxcl5zTEtRHFSTWtMTTZhZXM/edit?usp=sharing

                 

                Could you give me a step by step?

                 

                Starting from an arrow with no effects, and an acorn with no effects, what effects and groupings do you apply?

                • 5. Re: curious issue with extrude and rotate
                  mec_os Community Member

                  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.

                  • 6. Re: curious issue with extrude and rotate
                    asee23455 Community Member

                    Wow! Got it!

                     

                    In hindsight, it seems so obvious. The way I have the Extrude set up, it essentially creates a second arrow, .05" vertically above the lower one. So by adding that same vertical transform to the acorn, using the transform effect rather than the extrude effect, you get an acorn that rotates in the same way as the arrow.

                     

                    Thanks for talking me through this. It's a good and simple solution to a piddly, but enormously frustrating, problem.