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View Full Version : How to avoid UV Unwrapping distortion?

javierdl
03-23-2009, 07:29 PM
http://a5zi3w.bay.livefilestore.com/y1pLAyYo9LGSoT-RC9wORSG1P1L6kUpo7D0dUB9DPZ3B7XMMnAj55Q9sFPbvyGqLrQgTBaqLXtHqEIzXpoO9kdk8w/distorted_faces.gif

This is what Blender gives me when I select "Unwrap (smart projections)". Each of the cells is to match one of the 6 sides of a cube. Clearly these image cells are distorted vertically, as they are rectangles. Whereas the cube sides are squares.
Something you are to keep in mind, is that I am a total newbie to Blender, namely its UV Unwrapping methods. Secondly, the way I have been obtaining the unwrapping images is by means of screenshots :blush: (as I still haven't learned the proper way).
I did scale down vertically the resulting UVs (the ones above) in the UV/Image Editing window until each cell looked squared, and this seemed to have worked. But this is not exactly an elegant (nor reliable) solution.
How to avoid this then? Or, is there a more accurate way to fix while in the UV/Image Editing window?

Thanks in advance guys :)

JDL
Liquidape
03-23-2009, 08:09 PM
Smart projections just takes a look at each side of the cube and then expands them to fill the most space possible in the UV image editor. Of course you can just grab the vertices and square them off visually or, you can do a different unwrap. To do the other unwrap, you will have to mark seams for where you want the "cuts" to be in the unwrap. Use Ctrl-E->Mark Seam in order to mark seems. Once your seems are marked, hit U, and select Unwrap. This should probably do an unwrap of the cube you are more expecting.

Follow this tutorial to see more clearly what I am talking about:
http://wiki.blender.org/index.php/Doc:Manual/Textures/UV/Unwrapping_a_Mesh
Ian Jones
03-24-2009, 01:44 AM
I found when I just started unwrapping (a few days ago), I marked the seams correctly and unwrapped, but things looked a little wonky still. I could have corrected that manually, but instead it turns out you can change the method it uses to unwrap (using regular unwrap, not smart projections).

With the object selected go into Edit Mode > Find the UV calculation options (a tab with multires and texture face options) and select 'Angle based' rather than 'Conformal'. Obviously 'Conformal' has its uses (I haven't learnt about yet), but for a simple cube it doesn't work 100% correctly.
javierdl
03-24-2009, 02:15 AM
Thanks a lot both for your inputs guys :)
I'll look into both advices tomorrow when I'm more awake ;)
I can't wait already.

JDL
RendoGog
03-24-2009, 09:39 AM
The conformal mode works ok when you go into a orthagraphic projection such as top view, it seems to get screwed when you are in a 3d or camera view.
FreakyDude
03-24-2009, 03:41 PM
or you could select one side, say the front in front view, choose unwrap from view, pin those four verts in the UV window, select everything in the 3D window (assuming you have already placed your seams accordingly, and press unwrap. There ya go, a perfectly squared out uv map, you can scale and pack them together to fit the available space as much as you want.
javierdl
03-25-2009, 01:56 AM
Cool! Now I really have so much to learn :)

Thank you all!
Today I wasn't able to try anything, but tomorrow looks like I will, finally!

JDL

See other replies at BlenderArtists.org (http://blenderartists.org/forum/showthread.php?p=1344334#post1344334)
javierdl
03-26-2009, 10:45 PM
Liquidape (http://forums.cgsociety.org/member.php?u=354753),
I tried your advice and it worked like a charm! So easily too. I just can't believe that UV Unwrapping is this easy with Blender.
I have new respect for Blender :bowdown:

JDL
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