13.7 Quantity

The Quantity is a combination of a floating point number and Unit. It is used throughout the QW-Modeller (FreeCAD) to handle parameters and all other kind of input/output.

General

In a CAD or CAE environment it is very important to keep track on the unit of a variable. A lot of trouble can arise when mixing up units or calculating results in different unit systems.

For that reason the FreeCAD Quantity framework was created. It includes all the code and objects to deal with units, unit calculations, user input, and conversion in other unit systems and the pretty output of units and values. In the long run no parameter in FreeCAD should be just a number.

Supported Units

The FreeCAD input supports the following units and units-systems for dimensions:

• "nm"

• "µm"

• "mm"

• "cm"

• "dm"

• "m"

• "km"

• "in"

• "ft"

• "thou"

• "mil"

• "yd"

• "mi"

FreeCAD do use the Greek letter for micro but also accept 'u' as a replacement.