A really simple object won't unwrap properly

hi everyone. please see the attached blend file.
it contains one object. IT’s a sort of D shaped double sided plate, with a trim around it. The geometry is hardly very complex. The plate itself is just a quarter cut off a uvsphere and stretched a bit. The trim is an elongated cylinder wrapped around it. I’ve marked a seam all around the plate section, which should divide it neatly into front and back plates, and i’ve also marked a seam down one column of the trim, which should allow it to unwrap into a rectangular shape. There’s no logical reason why blender should have a problem here.

But i’m trying to unwrap it for texturing, and it’s just coming out disastrously. Blender adds curves and sharp edges where there weren’t any before, and completely wastes some 80% of the texture space it could be easily using if it did the job right.

I’ve attached an image of how the unwrapped UV looks to me, just in case anyone else unwrapping it gets a different result. I’m sure everyone can agree that’s abysmally bad uvmapping. All i’m doing is selecting all vertices in edit mode, hitting U, and selecting unwrap. nothing nonstandard.

I’d appreciate anyone who could take a look, and maybe try to figure out why blender would be tripping up on this shape. My ideal unwrap would be two D shaped plates and a flat rectangle for the trim


plateUV.blend (1.23 MB)

Did you add seams?

Apply your scale and rotation for your model. You also have an internal face in the trim down below. Your object consists of two different parts so you can add seams and unwrap them separately.

Look at your objects scale values for each axis.
In object mode use Ctrl+A / scale

big thanks to richard and JA12 :slight_smile: applying the scale and rotation was the answer

Ok I’ve uploaded the file you provided with a correction - all I did was apply scale while in object mode (Object menu or Ctrl A). You might want to apply rotation as well - depends on your other objects.

It is recommended - and when you have multiple separate objects, essential - that you have them all at the same scale - 1.0, 1.0, 1.0 is the simplest.


I’d recommend getting all your origin points to the centre, or at least the same place - centre is by far the simplest to do.

I removed the faces from the d-shaped plate that is hidden by the ‘tube’; they are needless geometry imo. When you load the file below, you’ll also see I’ve highlighted a vert that needs deleting as it is the central point for hidden faces - probably from when you joined the two sections of tube together. It’s a small circle in the UV unwrap.


If you want to tweak the uv unwrap further, then alt-right click on a line of verts in the uv/image editor, press w, then select an option - auto align I use the most.

Hope it helps. :slight_smile:

EDIT: Hah, downloaded your file went to make a coffee - should have checked for replies first. :spin: