Property

Introduction

A property is a piece of information like a number or a text string that is attached to a LabRPS 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 LabRPS. As objects in LabRPS 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 FeaturePython Custom Properties and PropertyLink: InList and OutList

All property types

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

Name	Unit (if any)	Remark
Acceleration	m/s^2
AmountOfSubstance	mol
Angle	°
Area	m^2
Bool
BoolList
Color
ColorList
Density	kg/m^3
Distance	m
Enumeration
ExpressionEngine
File
FileIncluded
Float
FloatConstraint
FloatList
Font
Force	N
Frequency	Hz
Integer
IntegerConstraint
IntegerList
IntegerSet
Length	m
Link
LinkChild
LinkGlobal
LinkHidden
LinkList
LinkListChild
LinkListGlobal
LinkListHidden
LinkSub
LinkSubChild
LinkSubGlobal
LinkSubHidden
LinkSubList
LinkSubListChild
LinkSubListGlobal
LinkSubListHidden
Map
Material
MaterialList
Matrix
PartShape		a Part property, is accessed as `Part::PropertyPartShape`
Path
Percent
PersistentObject
Placement
PlacementLink
PlacementList
Position
Precision
Pressure	Pa
PythonObject
Quantity
QuantityConstraint
Rotation
Speed	m/s
Stiffness	m/s^2
String
StringList
UUID
VacuumPermittivity	s^4A^2 / (m^3kg)
Vector
VectorDistance
VectorList
Volume	l or m^3
XLink
XLinkList
XLinkSub
XLinkSubList

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: LabRPS scripting basics

A scripted object is created first, and then properties are assigned.

obj = App.ActiveDocument.addObject("WindLab::WindLabSimulation", "MyKaimalAlongWindSpectrum")

obj.addProperty("App::PropertyFloat", "Velocity", "Parameter", "Mean speed value")
obj.addProperty("App::PropertyBool", "Stationary", "Parameter", "Set stationarity")

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"