In the XCS program (xtool), it’s crucial to disable automatic resizing in the settings. When the working field is smaller than the file layout, the program tends to automatically shrink the details to fit within that limited space. However, this can lead to assembly issues and incorrect proportions
In most of my files I add a 10mm x 10mm square at the top left. You can measure it after importing the file, if the size matches, then there is no distortion. You can also measure any connection, protrusion or hole – one of the sides should be equal to the thickness of the material for which the file is intended.