When I unwrap my meshes, they seem to be skewed. for instance, the top of my rail piece is concave in stead of convex. I…

I am having the same issue , just on the top of the rail piece, did you figure it out? 

Here is a quick video of the settings, I couldnt find the scale values for just the rail piece in edit mode just for the whole model as you can see in the video. Let me know if you see anything that could help. Thanks.

https://drive.google.com/open?id=159GWCHXs68P1n3M0m6MTos-12Jn2qu1R

hmm, I just tried that and then cleared the seams and re-marked them and unwrapped but they are the same but maybe a bit more curved(still in the wrong direction)  the scale is now 1,1,1.

Also just tried to do a smart uv project and it actually set them the right way but when I tried again with my marked seams it is wrong.

https://drive.google.com/open?id=1FhvvK3ymgvBFSPi7juFaO25DuKd6181a

Thanks for the reminder @terence7 – After opening your file, it looks correct to me:

So I’m wondering if you’ve been laying our your UV’s with a non-square texture loaded in the UV image editor. Whenever laying out UVs, you want to ensure that either no image is loaded in the image editor or that a perfectly square image is loaded (1024×1024 pixels for example). See when I load a rectangular image, the UVs stretch to fit:

Ooooohhhh ok I see what you’re talking about. Yeah what is happening there..I guess that’s how the unwrapper is handling the n-gon there. I recommend you connect edges to get back to tris and quads (no n-gons):

*Adding edges where those blue lines are.* I bet you 1200 midichlorians that will force the unwrap to respect the dip.

Figured it out, instead of choosing each vertice and pressing f to make those edges, I deleted that whole face and recreated the faces and that worked!