UV maps are tilted?

I’ve attempted to google on this issue, couldn’t find anything.
For clarification: My uv maps are not warped, they appear to be tilted a few degrees.

Note how in the screenshot the line is on the top part of the background on the left, and near the bottom part on the right.

Some tearing is also visible on the line.

This makes it hard to properly align textures, so how do I prevent this from happening?

this kind of thiing happens a lot, mostly due to the uv’s trying to represent something in 2D in a way that isn’t really possible in real life. ( like trying to trying to flatten a ball for example) the more complex your mesh the more things don’t calculate properly. always try to mark your seams logically. if the model was a real thing, how would you cut it to make it lie flat without creasing or overlapping the thing? for small errors like this you can manually lighn the uvs by selecting the edges and scaling them to 0 on the x or y axis ( just select the edge andf type s, x, 0 or s, y, 0 depending on the alignment obviously!) there are a number of plugins that can help. for example, the UV tool plugin will automatically align all the UV’s into a grid or circle depending on your requirements. and there are several others that do a similar job

Hm. Not sure how the UV can’t represent geometric shapes on a 2d plane. I’ve modeled something in Sketchup using only rectangular flat faces, so I would suppose it’d not give much trouble.

Thanks anyway, I’ll try marking different seams + see if that helps.