SAFE works with two basic units: force and length. The program offers many different compatible sets of force and length units to choose from, such as “kip-in” or “N-mm.” Angular geometry is measured in degrees, and time in seconds.
Although any units may be used at any time while working with the model, e.g., inch units for beam sections and feet units for grid layout, it is important to select an appropriate unit set when initializing the model to reduce the possibility of round-off error. In other words, if work is being completed primarily in US units, US default units should be selected as the initial units. In such a case, Metric defaults would not be a good choice for the units because a conversion would always be required when saving the model, which could result in numerical variations.
SAFE offers support for numerous unit abbreviations when doing data entry. By appending an abbreviation, such as “, M, ft, psf, or cm to a numeric entry in an edit box, data may be entered in units different from those selected in the Units form. For example, assume that the length unit for section dimensions is set to inch in the Units form, but when entering the thickness for a mat foundation slab object, you wish to use feet. To do this, simply type “3ft” in the edit box on the form used to specify the slab object and the program will automatically convert that value to 36 inches.