Property: Difference between revisions

From FreeCAD Documentation
m (Link to "PropertyLink:_InList_and_OutList")
m (sorting)
Line 16: Line 16:
</translate>
</translate>
{{Code|code=
{{Code|code=
Angle
Bool
Bool
Circle
Color
ColorList
Distance
Enumeration
ExpressionEngine
File
FileIncluded
FilletContour
Float
Float
FloatList
FloatList
FloatConstraint
FloatConstraint
Angle
Distance
ExpressionEngine
Integer
Integer
IntegerConstraint
IntegerConstraint
Percent
Enumeration
IntegerList
IntegerList
String
StringList
Length
Length
Link
Link
LinkList
LinkList
LinkSubList
LinkSubList
Material
Matrix
Matrix
PartShape
Vector
Path
VectorList
Percent
VectorDistance
Placement
Placement
PlacementLink
PlacementLink
PythonObject
PythonObject
String
Color
StringList
ColorList
Vector
Material
VectorList
Path
VectorDistance
File
FileIncluded
PartShape
FilletContour
Circle
}}
}}
<translate>
<translate>

Revision as of 14:43, 30 July 2022

Introduction

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. See also PropertyLink:_InList_and_OutList

All property types

Custom scripted objects can use any of the property types defined in the base system:

Angle
Bool
Circle
Color
ColorList
Distance
Enumeration
ExpressionEngine
File
FileIncluded
FilletContour
Float
FloatList
FloatConstraint
Integer
IntegerConstraint
IntegerList
Length
Link
LinkList
LinkSubList
Material
Matrix
PartShape
Path
Percent
Placement
PlacementLink
PythonObject
String
StringList
Vector
VectorList
VectorDistance

Internally, the property name is prefixed with App::Property:

App::PropertyBool
App::PropertyFloat
App::PropertyFloatList
...

Remember that these are property types. A single object may have many properties of the same type, but with different names.

For example:

obj.addProperty("App::PropertyFloat", "Length")
obj.addProperty("App::PropertyFloat", "Width")
obj.addProperty("App::PropertyFloat", "Height")

This indicates an object with three properties of type "Float", named "Length", "Width", and "Height", respectively.

Scripting

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 object's addProperty() method. On the other hand, View properties are normally provided automatically by the parent object from which the scripted object is derived.

For example:

  • Deriving from App::FeaturePython provides only 4 View properties: "Display Mode", "On Top When Selected", "Show In Tree", and "Visibility".
  • Deriving from Part::Feature provides 17 View properties: the previous four, plus "Angular Deflection", "Bounding Box", "Deviation", "Draw Style", "Lighting", "Line Color", "Line Width", "Point Color", "Point Size", "Selectable", "Selection Style", "Shape Color", and "Transparency".

Nevertheless, View properties can also be assigned using the view provider object's addProperty() method.

obj.ViewObject.addProperty("App::PropertyBool", "SuperVisibility", "Base", "Make the object glow")

Source code

In the source code, properties are located in various src/App/Property* files.

They are imported and initialized in src/App/Application.cpp.

#include "Property.h"
#include "PropertyContainer.h"
#include "PropertyUnits.h"
#include "PropertyFile.h"
#include "PropertyLinks.h"
#include "PropertyPythonObject.h"
#include "PropertyExpressionEngine.h"