Unit System of OpenSTAAD:
The values that are returned by API's will be determined by the current base unit.
If the base unit is English, then all values that are derived from a length unit, e.g. dimensions, areas, coordinates, will be based on inches, 'in'. All values derived from a force unit, e.g. Axial force, moments, stresses, etc, will be based on kilopounds, 'KIP'
If the base unit is Metric, then all values that are derived from a length unit, will be based on Meters, 'm'. All values derived from a force unit, will be based on kilo newtons, 'kNs'
Note that there is a function available to obtain the current base unit GetBaseUnit
Return values of function GetBaseUnit:
Sample VBA Syntax of function GetBaseUnit
Dim objOpenStaad As Object
Dim nReturn As Long
Set objOpenStaad = GetObject(,"StaadPro.OpenSTAAD")
nReturn = objOpenStaad.GetBaseUnit