A property is a piece of information like a number or a text string that is attached to a FreeCAD document or an object in a document. Public properties can be viewed and modified in the Property editor.
Properties play a very important role in FreeCAD. As objects in FreeCAD are "parametric", this means that their behavior is defined by their properties, and how these properties are used as input for their class methods.
All property types
Custom scripted objects can use any of the property types defined in the base system:
Bool Float FloatList FloatConstraint Angle Distance Integer IntegerConstraint Percent Enumeration IntegerList String StringList Length Link LinkList LinkSubList Matrix Vector VectorList VectorDistance Placement PlacementLink Color ColorList Material Path File FileIncluded PartShape FilletContour Circle
Internally, the property name is prefixed with
App::PropertyBool App::PropertyFloat App::PropertyFloatList ...
See also: FreeCAD scripting basics
A scripted object is created first, and then properties are assigned.
obj = App.ActiveDocument.addObject("Part::Feature", "CustomObject") obj.addProperty("App::PropertyFloat", "Velocity", "Parameter", "Body speed") obj.addProperty("App::PropertyBool", "VelocityEnabled", "Parameter", "Enable body speed")
In general, Data properties are assigned by using the document's
addProperty() method. On the other hand, View properties are normally provided automatically by the parent object from which the scripted object is derived.
- Deriving from
App::FeaturePythonprovides only 4 View properties: Display Mode, On Top When Selected, Show In Tree, and Visibility.
- Deriving from
Part::Featureprovides 17 View properties: the previous four, but also Angular Deflection, Bounding Box, Deviation, Draw Style, Lighting, Line Color, Line Width, Point Color, Point Size, Selectable, Selection Style, Shape Color, and Transparency.