Why is my UV flipping 90 degrees, and how do I scale it properly?

So lets say I have a image texture of a piece of road, which is according to the website,supposed to be 1600x800cm (16x8 meters)

Now, when I make a plane that has the same dimensions, and apply the road to it… it looks perfect.
But here come the first problem
As soon as I UV unwrap this (smart UV)… the image texture turns 90 degrees. Why is this?

But more importantly… I would like the road to be longer, lets say by factor 2… So I scale my plane to be 16*2 (32m) x 8… so only a X scale. I then apply the scale, reset the UV en unwrap it again. Then I change the scale of the entire texture to 4 in the mapping node… But that also gives me a wacky result…

So I think im doing something wrong in the UV unwrappen. Its just a simple plane, so im not sure what im doing wrong here…

Here is the node setup, im using the UVmapping node from Poliigon

It would be hard to figure this out as you’re not using the standard nodes, so it’s possible the “normal” answers may not apply.

Off course you are right…but I also just tried this with using the normal setup, and the results are the same. The image rotates as soon as I UV unwrap

If you go into the UV editor, you’ll probably find that your UV is simply rotated 90 degrees. Seems an easy fix. Also, for a flat plane, SmartUV isn’t really neccesary. A simple unwrap should do just fine.

Alternatively, in the mapping node, you could simply just rotate it the right way there.

Thanks for your reply… I understand the solution, but im just wondering why it would rotate it (for no reason)

Additionally, can someone tell me when I should scale a texture in the UV editor, and when should I just use the mapping node? Or is there no real difference?

Because Blender doesn’t know what the right way is. Unless it’s rotating the actual image and not the UV (which would be weird) then it’s simply because of that.

As for scaling in the UV, it depends on what you’re texturing. If you’re texturing a repeating pattern, then you can scale in either UV or with the mapping node - though, a lot of people would stick to just the mapping node, as you can be far more precise.

Ah ok that makes sense… Its sometimes easy to assume that Blender knows everything haha

And ok, so there’s no real difference in output between the two…except the actual way of doing it…gotcha…thanks!

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