How to translate dimensions when exporting an object/mesh from Blender to an STL file?

Question

3D printers

The problem is this: in Blender, on purpose, so that nothing is mixed in, I leave a bare mesh / object on the desktop of the program, with the removal of all textures from the file, I reset all scales and rotations via CTRL + A to ones and zeros. I always set the size of the object in millimeters.

Next, I export it to an STL file, for subsequent transfer to a friend for 3D printing on his photopolymer machine. So a friend reports each time that the dimensions of the object in the slicer become microscopic. As a result, you also have to write down the dimensions of the object (in mm) along all three axes separately in a text notebook, so that your friend drives in - Karl! - them manually in the slicer of a 3D machine!

What am I doing wrong when exporting an object from Blender to STL 3D printing format? How to transfer correct dimensions when exporting?

Answer 1

If you haven't changed the unit settings, then Blender's 1 meter is equal to 1 millimeter in STL (or OBJ).
Either take this into account when modeling, or scale up the model by 1000x before exporting.