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I am having trouble finding a way to rotate a shape to make a mesh. I found Youtube examples using older versions of Blender but none for the one we are using in the class I teach. We are building a Civil War scene. It includes Ft. Sumter and a Steamship plus various items including a cannon. I've decided to show my students two ways to make a cannon, if I can. Here attached are some images that show my approaches. I can show them how to do the modeling using a UV Sphere, but I think it is important to show both methods. There should be some kind of menu option that asks for a line that would act as a rotation axis.enter image description here

enter image description here

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  • $\begingroup$ Hi Randy, you should accept the best answer as correct, I noticed you don't do this and your questions have some good views. Pls do it for all your questions thanks:) $\endgroup$ – Jaroslav Jerryno Novotny Feb 10 '15 at 16:30
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You can use a Screw Modifier. Being in Object Mode select your profile and enable the modifier. enter image description here

You have now a bunch of extra options. Set the desired axis you want your profile to screw along. Set the Angle to 360 degrees to have the whole form (or 180 if you want to have a half of the form). You may also increase the number of the Steps, so if you apply the modifier later you'll have more geometry. Please see this documentation for more details: http://wiki.blender.org/index.php/Doc:2.6/Manual/Modifiers/Generate/Screw enter image description here

You may notice the strange behaviour of the normals after applying the modifier. Recalculate them using a Tool Shelf button or use the Ctrl+N shortcut, while in Edit Mode. enter image description here


UPDATE: Placing the origin point to make the Screw Modifier work properly (according to Randy's situation).

I started with placing the inner vertices of the profile perfectly on the one axis. Then I gave the mesh the same rotation and the origin point the same location like on your printscreens. enter image description here

  1. I entered the Edit Mode and selected two vertices as pictured below. Then snapped the cursor to selection using shortcut: Shift+S-->Cursor to Selected.
  2. I entered the Object Mode and snapped the origin point to 3D cursor using Tool Shelf button (you may also use the shortcut: Alt+Ctrl+Shift+C-->Origin to 3D cursor).
  3. With the origin point set I enabled the Screw Modifier. enter image description here
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    $\begingroup$ Even better, as you can just edit the one profile if at any time you want to make some changes. +1 $\endgroup$ – VRM Feb 9 '15 at 18:14
  • $\begingroup$ I didn't remember this modifier. Both answers are good, +1 to both :) $\endgroup$ – Bithur Feb 9 '15 at 18:28
  • $\begingroup$ Ok, I got this but the axis was not in the right place so it rotated wrong for me. Then when I tried to undo this modifier, it undid some of the vertices instead. Now when I try to start over with a new set of lines, Blender is set to screw the new lines before I want it to happen. Help! $\endgroup$ – Randy Van Nostrand Feb 9 '15 at 19:32
  • $\begingroup$ Redid this three times. The last time was the closest. Still, the axis of rotation varied from ideal. How do I position the 3D cursor more accurately so as to make the axis of rotation where I want it to be? $\endgroup$ – Randy Van Nostrand Feb 9 '15 at 20:12
  • $\begingroup$ @Randy, I've updated the answer. Please check it out. $\endgroup$ – Paul Gonet Feb 10 '15 at 12:56
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What you are looking for is the Spin tool. Set the 3D Cursor to the position you want to spin around (generally the origin) and then press Alt+R. You will notice a bunch of options come up:

Spin Tool Options

This is located in the left menu, opened by pressing T.

Spin Tool GIF

Also you will need to remove doubles by selecting all vertices, and pressing W > Remove Doubles

For detailed information on all of the capabilities, go to the official documentation page.

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    $\begingroup$ don't forget to remove doubles when using spin tool. Center (xSteps) and 360° vertices are dupicates. $\endgroup$ – Bithur Feb 9 '15 at 18:22
  • $\begingroup$ How are you doing that quick mode select thing in the gif? Is it an addon? $\endgroup$ – Gwen Dec 23 '15 at 17:48
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    $\begingroup$ @Gwenn It is an official addon bundled with blender called Pie Menus, quite handy $\endgroup$ – VRM Dec 23 '15 at 17:50

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