Редактор на свойства на обектите
Редактора на свойствата на обектите е един от най-важните инструменти в FreeCAD. В него може да променяте всяко свойство (например размер, позиция, ориентация) на обект във вашия докумен.
Редактора ви показва свойствата само на избрания в момента обект, в активния в момента документ (внимавайте кои е в момента активния документ, ако имате няколко документа отворени). Ако не сте избрали обект (или няма обект), редактора на свойствата ще е празен.
Не всички свойства могат да бъдат променени във всеки един момент. В зависимост от контекста някои свойства няма да могат да се променят.
Empty property editor, when no object is selected.
Дефиниция на свойство на обект
"Свойство на обект" е информация (число, текст) свръзано с определен обект в документ на FreeCAD document or an object in a document. Свойствата могат да се виждат, и ако е разрешено в определния контекст, да се променят с редакторът на свойствата.
Свойствата играят важна роля в FreeCAD, тъй като те са основния механизъм за променяне на параметрите на обектите. Свойствата определят точната форма на обектите.
Скриптираните обекти в FreeCAD могат да имат свойства от следните типове:
Boolean Float FloatList FloatConstraint Angle Distance Integer IntegerConstraint Percent Enumeration IntegerList String StringList Link LinkList Matrix Vector VectorList Placement PlacementLink Color ColorList Material Path File FileIncluded PartShape FilletContour Circle
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 the document.
Some of the most commonly used property types are:
App::PropertyBool App::PropertyFloat App::PropertyAngle App::PropertyDistance App::PropertyInteger App::PropertyString App::PropertyMatrix App::PropertyVector App::PropertyPlacement
Различни обекти могат да имат различни свойства. Някои свойства обаче (например позиция и ротация) присъстват за всички обекти.
View and Data properties
There are two classes of feature properties accessible through tabs in the property editor:
- View properties, related to the "visual" appearance of the object. The View properties are tied to the ViewProvider (
ViewObjectattribute) of the object, and are only accessible when the graphical user interface (GUI) is loaded. They are not accessible when using FreeCAD in console mode, or as a headless library.
- Data properties, related to the "physical" parameters of the object. The Data properties define the essential characteristics of the object; they exist at all times, even when FreeCAD is used in console mode, or as a library. This means that if you load a document in console mode, you can edit the radius of a circle or the length of a line, even if you cannot see the result on the screen.
For this reason, Data properties are considered to be more "real", as they truly define the geometry of a shape. On the other hand, View properties are less important because they only affect the superficial appearance of the geometry. For example, a circle of 10 mm radius is different from a circle of 5 mm radius; the color of the circle (view property) doesn't affect its shape, but the radius does (data property). In many instances in this documentation, the word "property" is understood to refer to a "Data property" and not to a "View property".
See also: Object name
The most basic scripted object won't show any Data property in the property editor, except for its
Label attribute. The
Label is a user editable string that identifies the object in the tree view. On the other hand, the
Name attribute of an object is assigned at the moment of its creation and cannot be changed; this attribute is read-only, and is not displayed in the property editor either.
A basic parametric object is created as follow
obj = App.ActiveDocument.addObject("App::FeaturePython", "App__FeaturePython") obj.Label = "Plain_object" print(obj.Name) print(obj.Label)
View and Data tabs of the property editor, for a basic "App::FeaturePython" scripted object.
For 2D geometry, most objects are derived from
Part::Part2DObject (itself derived from
Part::Feature) which is the base of Sketches, and most Draft elements. See Part Part2DObject for the most basic properties that these objects have.
Right clicking in an empty space of the view, or with a property selected, shows only one command:
- Show all: if active, in addition to the standard properties that appear already, it shows all the hidden Data and View properties in their respective tabs.
- Data: "Proxy", "Label2", "Expression Engine", and "Visibility".
- View: "Proxy".
When the Show all option is active, and one property is selected, more actions are available with a second right click:
- Show all: deactivates the Show all command, hiding the additional Data and View properties.
- Add Property: adds a dynamic property to the object; this works with both C++ defined objects, and Python scripted objects.
- Expression...: brings up the formula editor, which allows using expressions in the property value.
- Hidden: if active, sets the property as hidden, meaning that it will only be displayed in the property editor if Show all is active.
- Output: if active, sets the property as output.
- NoRecompute: if active, sets the property as not recomputed when the document is recomputed; this is useful when a property should be kept unaffected by other updates.
- ReadOnly: if active, sets the property to be read-only; it won't be editable in the property editor any more until this switch is turned off. The Expression... menu entry is no longer available. Note: It may be still possible to change the property via a dialog that updates the property.
- Transient: if active, sets the property as transient. The value of a transient property is not saved to file. When opening a file, it is instantiated with its default value.
- Touched: if active, it becomes touched, and ready for recompute.
- EvalOnRestore: if active, it is evaluated when the document is restored.
Example of the properties of a PartDesign object
In this section we show some common properties that are visible for a PartDesign Body, and one PartDesign Feature. The specific properties of an object can found in the specific documentation page of that object.
Most of these properties are inherited from the Part Feature basic object.
- ВидAngular Deflection: it is another way to specify how finely to generate the mesh for rendering on screen or when exporting. The default value is 28.5 degrees, or 0.5 radians. The smaller the value the smoother the appearance will be in the 3D view, and the finer the mesh that will be exported.
- ВидBounding Box: indicates if a box showing the overall extent of the object is displayed.
- ВидDeviation: sets the accuracy of the polygonal representation of the model in the 3D view (tessellation). Lower values indicate better quality. The value is in percent of object's size.
- ВидDisplay Mode: display mode of the entire Body,
- ВидDisplay Mode Body: display mode of the Tip of the Body,
- ВидDraw Style:
Dashdot; defines the style of the edges in the 3D view.
- ВидLine Color: the RGB color of the edges, it defaults to
(25, 25, 25).
- ВидLine Width: the thickness of the edges, it defaults to
- ВидOn Top When Selected:
- ВидPoint Color: the RGB color of the vertices, it defaults to
(25, 25, 25).
- ВидPoint Size: the size of the vertices, it defaults to
- ВидSelectable: whether the object is selectable or not.
- ВидSelection Style:
- ВидShape Color: the RGB color of the shape, it defaults to
(204, 204, 204).
- ВидShow In Tree: if it is
true, the object appears in the tree view. Otherwise, it is set as invisible.
- ВидTransparency: the degree of transparency from
- ВидVisibility: whether the object is visible in the 3D view or not. Toggle with the bar in the keyboard.
In this case we observe the properties of the PartDesign Revolution feature.
- ДанниLabel: the user defined name given to the object, this can be changed as desired.
- ДанниRefine: whether to refine the fusion done with other objects.
- ДанниBase: the point in space that specifies where the revolution takes place. It cannot be modified directly, only when editing the feature.
- ДанниAxis: the axis around which the revolution will be performed. It cannot be modified directly, only when editing the feature.
- ДанниAngle: the angle that specifies how much of the base element is rotated. By default it is
360 deg, but it can be any fraction of that.
- ДанниMidplane: if the base object is a Sketch, when this property is
true, it will perform the revolution with the sketch serving as a plane of symmetry. This is noticeable if the ДанниAngle is different from
- ДанниReversed: by default it is
true. Whether to perform the revolution in one direction or the other.
See also: FreeCAD Scripting Basics.
Most properties that are visible in the property editor can be accessed from the Python console. These properties are just attributes of the class that defines the selected object. For example, if the property editor shows the ДанниGroup property, this means that the object has the
These attributes (properties) are added with the
addProperty method of the base object. At least it is necessary to specify the type of property, and its name.
obj.addProperty("App::PropertyFloat", "Custom") print(obj.Custom)
Properties follow the
PascalCase convention, meaning that each word starts with a capital letter, and there are no underscores. When the property editor displays such names, it leaves a space between each capital letter, making it easier to read.
obj.addProperty("App::PropertyDistance", "CustomCamelProperty") obj.CustomCamelProperty = 1000 print(obj.CustomCamelProperty)
Property editor showing the Data properties of a PartDesign Body, with two additional properties, "Custom" and "Custom Camel Property".
In similar way the View properties are added, not to the base object, but to its
ViewObject. Then, it follows that properties like ВидAngular Deflection, ВидBounding Box, ВидDisplay Mode, ВидDisplay Mode Body, ВидLine Color, and others, can be examined and changed from the Python console.
print(obj.ViewObject.AngularDeflection) print(obj.ViewObject.BoundingBox) print(obj.ViewObject.DisplayMode) print(obj.ViewObject.DisplayModeBody) print(obj.ViewObject.LineColor)
All public properties of the object, and of its view provider, are contained in the corresponding