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Handles

Handles are a feature of a PythonPart, which improves the user's experience by allowing him to edit the geometry (or in some cases also non-geometrical properties) directly in the model view. The user can be provided a possibility to perform various operations e.g.:

  • changing a dimension with dimension handle
  • define a coordinate with coordinate handle
  • execute action with button handle
  • hiding or displaying a component with checkbox handle
  • increment a dimension with increment handle
  • input an angle with rotation handle

A handle can be assigned to a PythonPart parameter. If that is the case, it is possible to show an input field directly inside the viewport.

Definition

Handle is created by instantiating the class HandleProperties. Object of this class represents a handle. Handle processing differs depending on whether the PythonPart is an interactor or not. Please refer to the relevant subsection to learn more.

The composition of the HandleProperties class is shown below.

classDiagram
    direction BT

class Point3D {
    float X
    float Y
    float Z
}
class ElementHandleType{
    <<Enumeration>>
    HANDLE_ARROW
    HANDLE_CIRCLE
    HANDLE_SQUARE_BLUE
    HANDLE_SQUARE_EMPTY
    HANDLE_SQUARE_RED
    HANDLE_SQUARE_RIGHT
}
class HandleDirection{
    <<Enumeration>>
    X_DIR
    Y_DIR
    Z_DIR
    XY_DIR
    XZ_DIR
    YZ_DIR
    XYZ_DIR
    POINT_DIR
    ANGLE
    Z_COORD
    PLANE_DIR
    VECTOR_DIR
    CLICK
}
class HandleParameterType{
    <<Enumeration>>
    X_DISTANCE
    Y_DISTANCE
    Z_DISTANCE
    POINT
    POINT_DISTANCE
    ANGLE
    Z_COORD
    VECTOR_DISTANCE
    CHECK_BOX
    INCREMENT_BUTTON
    DECREMENT_BUTTON
}
class HandleParameterData{
    <<Dataclass>>
    +str param_prop_name
    +HandleParameterType param_type
}
class HandleProperties{
    +str handle_id
    +Point3D handle_point
    +Point3D ref_point
    +List[HandleParameterData] parameter_data
    +HandleDirection handle_move_dir
    +ElementHandleType handle_type
}

Point3D "2" ..> HandleProperties
ElementHandleType ..> HandleProperties
HandleDirection ..> HandleProperties
HandleParameterData ..> HandleProperties
HandleParameterType ..> HandleParameterData

Handle type

The enumeration class ElementHandleType defines the layout of the handle. The default value when instantiating the class HandleProperties is HANDLE_CIRCLE and can be changed to one of the following:

Layout Type
Handle arrow HANDLE_ARROW
Handle circle HANDLE_CIRCLE
Handle square blue HANDLE_SQUARE_BLUE
Handle square empty HANDLE_SQUARE_EMPTY
Handle square red HANDLE_SQUARE_RED
Handle square right HANDLE_SQUARE_RIGHT

Handle parameter data

The data class HandleParameterData connects the handle to a specific PythonPart parameter defined in the .pyp file. Thanks to this, a parameter value is recalculated every time a connected handle is modified. The recalculation is performed depending on the defined HandleParameterType.

Handle parameter type

The enumeration class HandleParameterType defines how the value of the parameter property assigned to the handle should be recalculated, when the handle is modified. Please refer to the API reference to see, what recalculation methods are available.

Handle direction

The enumeration class HandleDirection defines the allowed direction, in which the handle can be moved when being modified. Please refer to the API reference to see the available options.

Processing

In standard PythonPart

Creation

In order to create a standard PythonPart with handles, organize the HandleProperties objects representing the handles in a list, and assign them to the handles attribute of the CreateElementResult object, returned at the end of the create_element() function:

def create_element(build_ele, doc):
    ...
    handle_1 = HandleProperties(...)
    handle_2 = HandleProperties(...)

    handle_list = [handle_1, handle_2]
    ...
    return CreateElementResult(elements = model_elements_list,
                               handles =  handle_list)

Modification

After every handle modification, the new value of the property must be written back in the property palette and the element must be recreated. To handle this process, implement the function move_handle() in your script. Use the HandlePropertiesService to update the parameter values

Example

def move_handle(build_ele,
                handle_prop: HandleProperties,
                input_pnt:   NemAll_Python_Geometry.Point3D,
                doc:         NemAll_Python_IFW_ElementAdapter.DocumentAdapter):
    if handle_prop.handle_id == build_ele.MirrorCuboid.name: #(1)!
        build_ele.MirrorCuboid.value = not build_ele.MirrorCuboid.value

    else:
        HandlePropertiesService.update_property_value(build_ele, handle_prop, input_pnt) #(3)!

    return create_element(build_ele, doc) #(2)!
  1. You can process a specific handle (in this case the MirrorCuboid handle) differently. as the framework gives the handle name to the move_handle() function.
  2. The PythonPart must be recalculated with every movement of the handle.
  3. For a standard case you just need to implement this line of code in the move_handle function. The update_property_value method updates the values in the property palette after the handle is modified.

In Script Object

Implementing a handle functionality in a PythonPart implemented as a script object looks exactly the same, as in a standard PythonPart. Have a look on the paragraph above.

Handling the event of a handle being moved is also very similar: instead of a function, you have to implement a method, i.e. move_handle. It gets called after the user selects a handle and moves it around. Each movement triggers a call, so the geometry can be recalculated and redrawn on the run. The handle_prop argument contains the modified handle, and the input_point the position of the mouse on the screen. Like in a standard PythonPart, use the HandlePropertiesService to update the parameter values inside the BuildingElement. At the end, call the execute method to recalculate the geometry with these new values:

def move_handle(self,
                handle_prop: HandleProperties,
                input_pnt  : AllplanGeo.Point3D) -> CreateElementResult:

    HandlePropertiesService.update_property_value(self.build_ele, handle_prop, input_pnt)

    return self.execute()

Example

The complete implementation is shown in the PythonPart Handles, located in:

  • ...\Etc\PythonPartsExampleScripts\BasisExamples\General\Handles.py
  • ...\Etc\Examples\PythonParts\BasisExamples\General\Handles.pyp

In interactor

In an interactor PythonPart, the class HandleModificationService can be used to implement the handle processing. The service can be created like

handle_modi_service = HandleModificationService(coord_input, build_ele_list, control_props_list)

Depending on an defined InputMode, the HandleModificationService can be used for the selection and modification of the handles as follows

if input_mode == InputMode.RefPoint:
    input_pnt = coord_input.GetInputPoint(mouse_msg, pnt, msg_info).GetPoint()

    ...
#----------------- Select a handle
else:
    result = handle_modi_service.process_mouse_msg(mouse_msg, pnt, msg_info)

In the member function process_mouse_msg the selection and modification of the handle is executed and the value of the assigned property is checked and updated.

Example

A full implementation of the HandleModificationService processing, including how to start and stop the handle input, is provided in HandleUsageInInteractor located in:

  • …\etc\Examples\PythonParts\InteractorExamplesGeneral\HandleUsageInInteractor.pyp
  • …\etc\PythonPartsExampleScripts\InteractorExamplesGeneral\HandleUsageInInteractor.py

Examples

All the examples shown here are included into one PythonPart Handles, located in:

  • ...\Etc\PythonPartsExampleScripts\BasisExamples\General\Handles.py
  • ...\Etc\Examples\PythonParts\BasisExamples\General\Handles.pyp

Dimension handle

Let's say we have a simple geometry (a cube), and we want to let the user control a single dimension of it (the height) with a handle. The implementation can look like this:

<Parameter>
    <Name>CubeHeight</Name>
    …
    <ValueType>Length</ValueType>
</Parameter>

handle_parameter_data = HandleParameterData("CubeHeight", HandleParameterType.Z_DISTANCE) #(1)!

handle_height = HandleProperties("HeightHandle",
                                AllplanGeo.Point3D(0,0, build_ele.CubeHeight.value),
                                AllplanGeo.Point3D(),
                                [handle_parameter_data], #(2)!
                                HandleDirection.Z_DIR) #(3)!

handle_list.append(handle_height)
  1. The handle is connected here to the parameter CubeHeight with the Z_DISTANCE recalculation method, meaning that after every handle modification a distance vector between reference point and handle point is calculated and only the Z component is being put back a value to the parameter CubeHeigth.
  2. Here we could let one handle affect several parameters in the property palette, each in a different way.
  3. The handle should move only in local Z-direction of our PythonPart.

Coordinate handle

Let's say, we want to let the user control the ground view dimensions (length and width) of the PythonPart with a single handle.

<Parameter>
    <Name>CubeLength</Name>
    ...
    <ValueType>Length</ValueType>
</Parameter>

<Parameter>
    <Name>CubeWidth</Name>
    ...
    <ValueType>Length</ValueType>
</Parameter>

handle_parameter_data_list = [HandleParameterData("CubeLength", 
                                                    HandleParameterType.X_DISTANCE,
                                                    False), #(3)!
                                HandleParameterData("CubeWidth",
                                                    HandleParameterType.Y_DISTANCE,
                                                    False)] #(1)!

handle_length_width =  HandleProperties("LengthWidthHandle",
                                        AllplanGeo.Point3D(build_ele.CubeLength.value,
                                                            build_ele.CubeWidth.value,
                                                            0),
                                        AllplanGeo.Point3D(),
                                        handle_parameter_data_list,
                                        HandleDirection.XY_DIR)

handle_length_width.info_text = "Ground view dimensions" #(2)!
  1. Two parameters should be assigned to this handle therefore a list is defined here.
  2. The string in the optional parameter info_text will be displayed ever time the user hovers the handle with the mouse.
  3. Unlike in the first example, the input field in the model view is hidden.

Button handle

Let's say we want the handle to perform some action (mirroring the object). We can place a button in the palette or define a button handle, visible directly in the model view to do that.

<Parameter><!--(1)!-->
    <Name>MirrorCuboid</Name>
    <Value>False</Value>
    <ValueType>CheckBox</ValueType>
</Parameter>
  1. To be able to temporarily save the mirrored-status of the PythonPart a hidden parameter must be defined. In an Interactor PythonPart we could save this information ex. in a property of the interactor class.
mirror_handle = HandleProperties("MirrorCuboid", 
                                    point5,
                                    AllplanGeo.Point3D(),
                                    [], #(1)!
                                    HandleDirection.CLICK) #(2)!

mirror_handle.handle_type  = AllplanIFW.ElementHandleType.HANDLE_ARROW
mirror_handle.info_text    = "Mirror the cuboid"
mirror_handle.handle_angle = rot_angle #(3)!

handle_list.append(mirror_handle)
  1. Note that no parameter is assigned to the handle. The handle processing is done entirely in move_handle() function by the assigned handle ID MirrorCuboid.
  2. By assigning the handle direction CLICK the handle cannot be moved. The move_handle() is called, when the handle is clicked.
  3. The handle is rotated in XY plane to align with the rotation of the object.
def move_handle(build_ele,
                handle_prop: HandleProperties,
                input_pnt: AllplanGeo.Point3D,
                doc: AllplanEleAdapter.DocumentAdapter):

if handle_prop.handle_id == "MirrorCuboid": #(1)!
    build_ele.MirrorCuboid.value = not build_ele.MirrorCuboid.value #(2)!

return create_element(build_ele, doc)
  1. The name of the handle is stored in the property handle_id
  2. We use an invisible parameter to temporarily save the mirrored status. The value of the parameter is changed here every time the handle is clicked.

List parameter

Let's say we have a parameter defined as a python list containing Point3D and we want to define a handle for each of these points.

<Parameter>
    <Name>PolyPoints</Name>
    …
    <Value>[Point3D(500,-2000,0);
            Point3D(1000,-4000,0);
            Point3D(5000,-5000,0);
            Point3D(5000,-1000,0)]</Value>
    <ValueType>Point3D</ValueType>
</Parameter>

handle_list = []

for index, pnt in enumerate(build_ele.PolyPoints.value): #(2)!

    handle_param_data = HandleParameterData("PolyPoints",
                                            HandleParameterType.POINT,
                                            False, #(4)!
                                            list_index = index) #(1)!

    handle_list.append(HandleProperties("PolyPoints",
                                        pnt,
                                        AllplanGeo.Point3D(),
                                        [handle_param_data],
                                        HandleDirection.XYZ_DIR))

    handle_list[-1].info_text = "Point " + str(index + 1) #(3)!
  1. As the parameter is defined as list, this argument is now required. The parameter PolyPoints is a one-dimensional list, therefore the list_index is an integer. In case of a two-dimensional list, a list of two integer values must be provided: [index_row, index_column].
  2. As separate handle must be generated for each point, implementation in a loop is the best solution.
  3. Here we change the info text for the appended handle.
  4. We don't want the input fields to be shown for these handles.

Value decrement / increment

Let's say we do not want to allow the user to set a value of a certain parameter (ex. wall thickness) freely, but only increment or decrement it by 100 mm instead.

<Parameter>
    <Name>Thickness</Name>
    <Text>Thickness</Text>
    <Value>1000.</Value>
    <ValueType>Length</ValueType>
    <MinValue>0</MinValue>
    <MaxValue>10000</MaxValue>
    <IntervalValue>100</IntervalValue><!--(1)!-->
</Parameter>
  1. We do want the thickness to increment in 100 mm steps, therefore we also need to constrain the parameter in the property palette separately. Otherwise, the user could change the thickness freely using the palette.
#---------- incrementation handle

increm_handle_param_data = [HandleParameterData("Thickness", #(1)!
                                                HandleParameterType.INCREMENT_BUTTON,
                                                in_decrement_value = 100.)]

increment_handle = HandleProperties(handle_id=          "IncrementHandle",
                                    handle_point=       point2 + AllplanGeo.Point3D(200, 100, 0),
                                    ref_point=          AllplanGeo.Point3D(), #(2)!
                                    handle_param_data=  increm_handle_param_data,
                                    handle_move_dir=    HandleDirection.CLICK #(3)!
                                    info_text=          "Increment thickness by 0.1m") 

handle_list.append(increment_handle)


#---------- decrementation handle

decrem_handle_param_data = [HandleParameterData("Thickness", #(4)!
                                                HandleParameterType.DECREMENT_BUTTON,
                                                in_decrement_value = 100.)]

decrement_handle = HandleProperties(handle_id=          "DecrementHandle",
                                    handle_point=       point2 + AllplanGeo.Point3D(200, -100, 0), 
                                    ref_point=          AllplanGeo.Point3D(),
                                    handle_param_data=  decrem_handle_param_data,
                                    handle_move_dir=    HandleDirection.CLICK,
                                    info_text=          "Decrement thickness by 0.1m")

decrement_handle.handle_angle = AllplanGeo.Angle(math.pi)

handle_list.append(decrement_handle)
  1. Defining the handle parameter type this way implies adding the value of 100 mm to the parameter thickness.
  2. In case of a button handle, this argument is not relevant and can be set to (0,0,0).
  3. The increment button can be clicked, but not moved. This behaviour is defined here.
  4. Decrementing a value is a different recaltulation behaviour therefore a separate handle must be defined for that and it must be assigned to the same thickness parameter.

Rotation handle

Let's say we want to allow the user to input an angle (ex. to rotate a geometry) using handle. In this case we need to implement a handle like this:

    <Parameter>
        <Name>RotAngleZ</Name>
        <Text>Z rotation</Text>
        <Value>0</Value>
        <ValueType>Angle</ValueType>
    </Parameter>

rot_handle_param_data = HandleParameterData("RotAngleZ", 
                                            HandleParameterType.ANGLE) #(1)!

handle_z_rot = HandleProperties(handle_id=          "Z_Rotation",
                                handle_point=       poly_points[1], #(2)!
                                ref_point=          poly_points[1], #(3)!
                                handle_param_data=  [rot_handle_param_data],
                                handle_move_dir=    HandleDirection.ANGLE, #(4)!
                                abs_value=          True,
                                info_text=          "Z rotation handle")

handle_z_rot.info_text = "Z rotation handle"

handle_list.append(handle_z_rot)
  1. This option implies, that an angle value is being calculated between handle_point and ref_point
  2. The handle will be drawn in this point.

  3. Reference point for the value calculation. The value of the angle will be calculated between the local X-axis with the origin in the ref_point, and the line going through the ref_point and the handle_point. This implies a rotation around the local Z-Axis. By default, the directions of the local axes are the same as the global one and can be changed by providing an optional argument angle_placement, ex. like this:

    angle_placement = AllplanGeo.AxisPlacement3D(AllplanGeo.Point3D(),
                                                AllplanGeo.Vector3D(1000, 0, 0),
                                                AllplanGeo.Vector3D(0, -1000, 0))

  4. A handle can be moved in any direction, just like with XYZ_DIR, but an arc with arrow will be drawn when hovering with the mouse over the handle to indicate a rotation.