Completely new to me, and a good thing you mentioned about exporting to 3d-printing. When it comes to metric system and scaling there is considerations to be taken. Luckily the slicer software that came with my printer allows me to both auto-repair my model, center and freehand scale models. I suppose the reparing means normalize the faces. Now I have the knowledge to accurately scale the models and center them in the system before exporting to the slicer.
