Windchill supports a data type Real Number with Units. This data type is associated with a quantity of measure which is measured in a base unit associated to a measurement system.

When creating or editing an existing value of type Real Number with Units, Windchill uses the Measurement System preference applicable at the user and context level where the object is being created. Both Create and Edit UIs use the Measurement System preference as a label after the data entry field to indicate that values are expected to be in the stated unit. Also, during data entry, Windchill allows the user to specify units different than the ones called out in the preferred measurement system. The persisted data is shown in units that are called out in the preferred measurement system.

The Windchill REST Services framework honors the user preferences for the measurement system for the data type Real Number with Units. User level preferences take precedence over container level preferences. To use the measurement system of the container context level you must specify the value of the header PTC-Container-Context and the container level preference must be locked. If it is not locked then the container level preferences are ignored and global or user level preference takes precedence regardless of whether the PTC-Container-Context header value is set. The applied container context is available in the response header PTC-Applied-Container-Context.