> You are here: Previewing Print Jobs >Part Units > Unit Defaults

> ## Unit Defaults

> The first part added to a print job defines the unit of measure for the print job (and for all dialog boxes offering transformations).

> Since STL and SLC files do not include units information, the system must guess an appropriate unit for the part, based on its measurements. If the system's choice leads to a part not fitting in the build envelope, you have an oversize part (see Oversize Parts).

> If you later add a part that uses different units, the system will ask you to confirm the part's units.