I had difficulty importing a board outline from Autocad into Kicad. It worked, but the scale was wrong. The outline was the size of a pool table!
After trying a number of recommended approaches to no avail, I used Kicad’s measurement tool to measure the too-large outline along one of its dimensions. As I knew how big I wanted this to be I was able to work out that it was x times bigger than it should be.
I went back into Autocad, and used the ‘scale’ function to make the outline 1/x of the original size, and re-exported it as a DXF file. On importing this into kiCad. I was delighted to find that it was spot on. Exactly the right size.
I mention this as there seem to be others with similar problems of scale when doing this. Hopefully, they can use the same trick.successfully too.
I had poor results scaling on input when a board outline was exported in inches and imported into another project layer as mm. Even after scaling x25.4, the result was crude and simplified.
It didn’t work when I tried it, and I could make no sense of it. I suspect there may be a problem with the scaling algorithm somewhere. Doing it in Autocad worked fine though.
There may be a bug there, it may be worth reporting. It would be simpler to be able to use import scaling because it would work for all files, not just those which you can export from some other program.
@davidsrsb was this by any chance related to line widths? There is a bug (https://bugs.launchpad.net/kicad/+bug/1831496) that should be fixed in 5.1.5 where those were done before the scaling was applied so that may have been the cause of the issues.
Do you mean crude and simplified on the ARCs etc ?
Maybe the DXF exporter uses polyline approximations for arcs, and those can be based on absolute errors, which means scaling up makes things ‘look worse’ ?
