Unwrapping inner cylinder of 'hoop' :: bangs head on bricks ::

I have a hoop. It’s circular. Here are some close ups:


The hoop concerned forms the blue bit of this:


This will eventually become a futuristic ringworld, similar to what’s been popularized by Microsoft’s ‘Halo’ XBOX game franchise.

I want to place land formations on the inner curve of the hoop. I’ve done the artwork in Photoshop.

The problem is unwrapping this bastard! Forget about the green, chunky, outer bit: that’s a different, separate model part. But everytime I try to unwrap the simple inner hoop model I get curly, spaghetti-like sections of the model, like below:


(The bottom-most section, that overlaps and bends in on itself, is the section I want long and rectangluar.)

I would like one, even, rectangular strip for the inner cylinder. I don’t care about the outer faces of the hoop, just the inner.

Can anyone share tips on how to get one, unwarped UV rectangle for the inner cylinder out of Blender’s Unwrap algorithm?

You need to mark your seams. Select 2 edge loops (alt right click, then shift+alt right click), one on the circumference and one cross sectional, hit ctrl-e, mark seam. (a) select all verts, unwrap.

I reproduce vaguely your mesh… with a bit more geometry… and a different shape in fact… :smiley: But what matters remains the same.


I used no seam. I simply unwrapped all the inner faces (the flat ring) with Cylinder Projection from Top view in Orthographic mode. Then I pressed [CTRL I] to select all the rest and I did the same: Cylinder Projection.

To finish, I enlarged the whole UV map only on the X axis: [S], [X], 3.14, [ENTER]. Done!

If you wonder why Pi, activate the display of the area stretching in the [N] panel of the UV Editor, you’ll see that’s better this way.

From there, you can split the very long islands into smaller ones easier to manage. Just don’t forget to separate the new islands with [Y] before moving them… and don’t let vertices overlap each other too long if you don’t want Blender to make your blood pressure hit the roof. :wink:

Thx blenderallday: In fact, all seams were marked. The ‘orange’ shot of the hoop is in Object view, where seams aren’t displayed. Sorry: I should have been more clear about that.

I tried several variations for seam marking. I could never get the inner cylinder unwrapping to a rectangle :confused:

Did you see Kaluura’s post? s(he)'s got a perfect unwrap without seams. Using seams I get a nearly perfect rectangle, but as usual Kaluura’s got the goods.

Kaluura: Nailed it :slight_smile: Tahnk you!

What threw me is the orientation of the view! I had no idea that the Unwrap algorithm was dependent on the viewing angle you had of the object - That just seems weird to me. I thought that was what the ‘Project from View’ unwrap option was.

Again, thanks heaps for your help - SOLVED.