Units for UDF

What are the units for UDF?

While writing UDFs, the first and foremost thing to keep in mind is that all parameters assigned in UDFs have to be in SI units (whatever be the unit system used in the Fluent GUI).

The above is true except when solving user defined scalars (UDS). In this case the parameters that have to do with the UDS (such as diffusion coefficients) are not scaled but read directly from the UDF.