Like OpenSees, OpenSees Navigator can use any unit system as long as all the properties of the model are defined in a consistent manner using the desired unit system everywhere.
When you define materials, sections, and elements in OpenSees Navigator the input masks provide “example” property values that are using the US system (kip,in,F). These are only there to provide some guidance and can easily be changed to any other unit system.
So all you need to do is to make sure that all the properties you define are in the desired unit system and if you use any of the predefined default objects make sure that you change those property values to the same unit system you selected.
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