By default, Ansys Polydata (as well as Ansys Polyflow) ignores the system of units that you are using. Hence, by default, all values must be specified in accordance with your system of units, and the numerical values will be interpreted accordingly. In other words, if you do not explicitly specify a system of units in Ansys Polydata, you can use any system you want, as long as you are consistent.

A system of units in physics consists of a length unit, a mass unit, and a time unit. In most applications, the second (s) is used for the time unit. For convenience, the unit for length and mass, as well as the unit for temperature, may depend on the application being considered. You may therefore need to switch from one system of units to another.

The most common systems of units are the international MKS (meter, kilogram, second) unit system and its subset, the CGS (centimeter, gram, second) system. For temperature, the most commonly used units are Celsius and Kelvin. In an Ansys Polydata session, you can switch from one system of units to a different one (for example, from the MKS system to the CGS system, or vice versa). You can also specify different units for individual quantities (length, mass, time, temperature, or electric current), rather than using a standard system of units. This allows you to customize the units to match your data, thus simplifying the problem setup procedure by eliminating the need to convert the units yourself.