Smart UV project is ordering my faces incorrectly

Question

I have a png texture which I am trying to paste onto a soda can:

but when I UV uwrap, it looks like this, the logo is in two different parts of the can, and its upside down:

I suspect this is because my UV unwrapping is not 'numbering' the faces correctly and 'flipping' faces randomly for no reason. The screenshot below shows I have selected consecutive faces. But the UV has ordered them in the weirdest way possible.

What can I do to fix my UV unwrapping?

Here is the blender file if you'd like to investigate:

Answer 1

You should mark edges as seams on your model(Ctrl+E -> M), then unwrap UVs(U->U), then move and rotate the UVs on your texture to get desired results.

If you had a more detailed soda can with the form getting narrower at the top, unwrapping would not produce UV island that is straight. UvSquares add-on is very helpful in situations like that.

Answer 2

If you haven't already solved the problem with the other answer, here is a hack that should work. There are probably a lot of unnecessary details.

In the UV Editor of your .blend file, turn on UV Sync (1) and Vertex Select Mode (2). Then select the top row of vertices (3):

In the 3D viewport you will have this. I used Shift->Z to make it easier to see:

I put the 3D viewport into Front Orthographic view and selected all the edges:

The pressed Delete, but deleted Faces:

Select the top edge of what remains:

Shift->D to duplicate it. Press ESC to not move it. Then separate it by pressing P and choosing Selection:

Go into Object mode and choose the separated BezierCurve.002. Then Edit Mode, select the edge and E Z 10 to extrude a new section for the can.

Select all of what was just extruded and assign the Red Metal Material to it as it originally was:

Then select an edge and Mark Seam. Select all and for this unwrap, I used the Unwrap method:

It gives this result. You can select a line of vertices to see which is the top and rotate it accordingly, after selecting everything, if you want the top at the top:

In the UV Menu I checked Constrain To Image Bounds and moved the unwrap onto the image. I turned on Display Stretch:

Then S Y to fill the image:

If you want a bit of a margin around the unwrap just scale it in a bit.

In Object Mode you can join this new part to the base Ctrl->J