Editor Units
Unreal Engine allows to set units a projects work with in default. it may be done in Edit→Project Settings→Appearance (Editor)
- Switching the default units in Unreal Engine should not significantly affect performance. The Unreal Engine is designed to be flexible, allowing developers to work in the units they are most comfortable with. Although the default unit is centimetres, you can switch to other units without worrying about a negative impact on performance. However, there may be some issues with physics simulations that are sensitive to scaling. Physics and simulations in general are simpler and faster when working on a smaller scale. A change of 3 cm is simpler than a change of 0.03 m, scaling up is also easier than scaling down so it makes more sense to work with smaller units. For example NVIDIA GameWorks tools are all cm based as well.
- It is also important to note that changing units may cause compatibility issues with some third-party tools or assets that may be designed to work with specific units.