I finished my first pattern in Valentina 0.3.0.0 and produced a layout by the new layouting algorithm. Then I saved as pdf. The chatch is, that somehow the file is not in scale (neither as pdf neither as png, neither with inch, nor with centimeters). I went to a professional printing agency and emphrasized that it had to be in scale but it wasn't. Then I tried everything thinkable at home and it didn't work. I also tried with only one pattern piece on A4 - but neither the view on my desktop (100%) nor printing it from different PCs and with different options worked. I just now installed Valentina 0.3.1.0 and it did not work, either.
Issue #297 resolved