Klayout design dimensions vary after rotating by some angle

edited May 18 in KLayout Support

Each time I rotate a design, the dimensions keep varying. It is very important for my design to be precise. I didn't have this issue earlier but this seems to be happening not just with me, but with a few more people that I know as well. I have attached the images for your reference. The first image is the rotated design by 45 degrees and the second image is the one which was not rotated


  • Might have to do with vertices / origins snapping-to-grid?
    There are some options about how that acts. Non-manhattan
    rotations stand a good chance of putting something off-grid.
    What happens then, depends on settings.

  • Hi @nograd,

    GDS is a format that puts all coordinates on a multiple of the database unit (for example 1nm). So if you rotate something by 45 degree, the new vertexes will have to snap (that's math). It will never stay identical. That is a basic limitation, not something the got introduced recently.

    You can place a cell with a rotation angle of 45 degree. In that case, the coordinates will stay on grid (inside the cell), but at some point (latest when you manufacture a mask), the layout will be flattened and grid snapping will happen.


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