Unwrapping planar rectangle doesnt result in same rectangle in uv editor I have a planar mesh, but when i unwrap it, it gets distorted. So i gave up and marked every single edge as seam. But even unwrapping one single planar face doesnt result in the same object in the uv editor. In the image i marked the corresponding vertices in 3D View (top) and UV Editor (bottom). 

There are many faces within my mesh with this problem, so correcting this manually is no option.
Thanks in advance.
If you want to maintain the proportions of a planar mesh, set the view from top ortho, then press U "project from view" option.