You can set the metersPerUnit metadata on the stage using UsdGeom.SetStageMetersPerUnit. Convenience shortcuts for units are scoped in UsdGeom.LinearUnits (e.g. UsdGeom.LinearUnits.meters is 1.0 metersPerUnit)
Note
Fallback stage linear units are centimeters (0.01).
Warning
Existing objects will not be automatically scaled to adapt to the stage linear units. Learn more about stage linear units.