A2plus Workbench/zh-hans: Difference between revisions

From FreeCAD Documentation
No edit summary
No edit summary
Line 34: Line 34:
添加的零件越多,跟踪就越重要。 因此,A2plus提供了以下工具来移动和查看零件:
添加的零件越多,跟踪就越重要。 因此,A2plus提供了以下工具来移动和查看零件:


*要在装配体中移动零件,请在模型树中选择它,然后使用工具栏按钮[[Image:A2p MovePart.svg|24px]]。将零件放置在所需位置时,用鼠标左键单击。如果移动的零件已经具有约束,则将通过按下工具栏按钮[[Image:A2psolver.svg|24px]]进行相应放置,因为这将触发以解决装配体的所有约束。
*要在装配体中移动零件,请在模型树中选择它,然后使用工具栏按钮[[Image:A2p MovePart.svg|24px]]。将零件放置在所需位置时,用鼠标左键单击。如果移动的零件已经具有约束,则将通过按下工具栏按钮[[Image:A2p solver.svg|24px]]进行相应放置,因为这将触发以解决装配体的所有约束。
*要显示约束,请在模型树中将其选中,然后使用工具栏按钮[[Image:A2p ViewConnection.svg|24px]]。这将使整个装配透明,并突出显示通过约束连接的两个对象。要返回普通视图,请在组件中单击鼠标左键。
*要显示约束,请在模型树中将其选中,然后使用工具栏按钮[[Image:A2p ViewConnection.svg|24px]]。这将使整个装配透明,并突出显示通过约束连接的两个对象。要返回普通视图,请在组件中单击鼠标左键。
*要仅显示装配中的某些零件,请在模型树中选择这些零件,然后使用工具栏按钮[[Image:A2p Isolate Element.svg|24px]]。或者,您可以通过在模型树中选择某个零件并按{{KEY|Space}}来切换其可见性来隐藏该零件。
*要仅显示装配中的某些零件,请在模型树中选择这些零件,然后使用工具栏按钮[[Image:A2p Isolate Element.svg|24px]]。或者,您可以通过在模型树中选择某个零件并按{{KEY|Space}}来切换其可见性来隐藏该零件。

Revision as of 14:41, 28 December 2019

Other languages:

Introduction

A2plus工作台是外部工作台,用于在FreeCAD中的不同零件组装成一个装配体。

本文档介绍了A2plus 0.4.33或更高版本的使用。

Installing

A2plus工作台是FreeCAD的插件。 可以通过菜单工具→插件管理器轻松安装。 A2plus正在积极开发中,并将经常获得新功能。 因此,您还应该使用菜单工具→插件管理器定期对其进行更新。 A2plus代码是在GitHub上托管和开发的[1],也可以通过将其复制到FreeCAD的MOD目录中进行手动安装。

入门

首先,切换到FreeCAD中的A2plus工具栏。 要创建装配体,请在FreeCAD中创建一个新文件。 首先,该文件需要保存。 建议(但不是必需)将其保存在要装配的零件的同一文件夹中。

现在,可以使用工具栏按钮将零件添加到装配体中。 按钮将所选文件中的所有实体作为单个部分添加。 使用按钮时,您可以选择将文件的哪个实体作为零件导入。
默认情况下,第一个添加的零件会固定在一个固定位置。 (您可以稍后通过零件属性Data固定位置进行更改。)
可以使用工具栏按钮复制装配中已经存在的零件。
要编辑部件中的零件,请在模型树中选择它,然后使用工具栏按钮。 这将在FreeCAD中将零件在新选项卡中打开,或者如果文件已经打开,则切换到其选项卡。
要将零件中的更改导入到部件中,请单击工具栏按钮[[Image:A2p_ImportPart_Update.svg|24px] ]。

导入的零件将保留其外部依赖性,并且可以进行编辑。 但是,对于像螺丝这样定义明确的零件,阻止对其进行编辑很有用。 这可以通过工具栏按钮 24px实现,该按钮可将所选零件转换为原始零件的静态副本。

要保存装配体并随后将其关闭,可以使用工具栏按钮 24px

装配

通过在零件之间添加约束来完成零件的组装。 约束后,如果可能,A2plus将根据约束移动零件。
对于零件之间的复杂约束,A2plus可能无法解决约束。 因此,也可以参考故障排除部分中有关解决此类情况的策略。

通过按住Ctrl键并选择两个零件的边或面来添加零件之间的约束。 约束将附加在模型树中,并添加到受影响的零件。

保持追踪

添加的零件越多,跟踪就越重要。 因此,A2plus提供了以下工具来移动和查看零件:

  • 要在装配体中移动零件,请在模型树中选择它,然后使用工具栏按钮。将零件放置在所需位置时,用鼠标左键单击。如果移动的零件已经具有约束,则将通过按下工具栏按钮进行相应放置,因为这将触发以解决装配体的所有约束。
  • 要显示约束,请在模型树中将其选中,然后使用工具栏按钮。这将使整个装配透明,并突出显示通过约束连接的两个对象。要返回普通视图,请在组件中单击鼠标左键。
  • 要仅显示装配中的某些零件,请在模型树中选择这些零件,然后使用工具栏按钮。或者,您可以通过在模型树中选择某个零件并按Space来切换其可见性来隐藏该零件。
  • 要切换整个装配体的透明度视图,可以使用工具栏按钮
  • 使用正常的FreeCAD编辑可以使每个零件透明。但是,有时由于FreeCAD中的错误,在重新打开装配体时零件的透明度设置会丢失。解决方法是,可以使用工具栏按钮恢复透明度设置。

约束

创建约束时,按下约束工具栏按钮后将显示一个对话框:
Image:A2p_ConstraintPropertiesDialog.png
对于某些约束,它允许您修改约束方向。 使用按钮24px Solve,您可以预先检查是否可以用A2plus解决这个新约束。 如果不是,请查看故障排除部分。

A2plus provides the following constraints:

Point on Point

Select a vertex (point) on each part. The toolbar button adds the constraint pointIdentity. It will make the vertices coincident.

Point on Line

Select a vertex (point), or circular edge (will select its center point), or a spherical face (will also select its center point) on one part and an edge on the other part. The toolbar button adds the constraint pointOnLine. It will put the vertex on the edge.

Point on Plane

Select a vertex (point), or circular edge (will select its center point), or a spherical face (will also select its center point) on one part and a plane on the other part. The toolbar button adds the constraint pointOnPlane. The constraint dialog allows you to specify an offset between the point and the plane. This offset can also be flipped between both sides of the plane. If the offset is zero, the constraint will put the vertex on the plane.

Sphere on Sphere

Select either a spherical face or a vertex (point) on both parts. The toolbar button adds the constraint sphereCenterIdent. It will either make the center of the spheres, the center of the sphere and the vertex, or the vertices coincident.

Circular Edge on Circular Edge

Select a circular edge on both parts. The toolbar button adds the constraint circularEdge. The constraint dialog allows you to specify an offset between the edges. This offset can also be flipped. You can furthermore set the constraint direction and lock the rotation of the parts. If the offset is zero, the constraint will put the edges concentric in the same plane.

Axis Coincident

Select either a cylindrical face or a linear edge on both parts. The toolbar button adds the constraint axisCoincident. The constraint dialog allows you to specify the axis direction. The dialog allows you furthermore to lock the rotation of the parts. The constraint will make the axes or lines coincident.

Axis Parallel

Select either a cylindrical face or a linear edge on both parts. The toolbar button adds the constraint axisParallel. The constraint dialog allows you to specify the axis direction. The constraint will make the axes or lines parallel.

Axis on Plane parallel

Select either a cylindrical face or a linear edge on one part and a plane on the other part. The toolbar button adds the constraint axisPlaneParallel. The constraint will make the axis or line parallel to the plane.

Axis on Plane normal

Select either a cylindrical face or a linear edge on one part and a plane on the other part. The toolbar button adds the constraint axisPlaneNormal. The constraint will make the axis or line normal to the plane.

Plane Parallel

Select a plane on both parts. The toolbar button adds the constraint planesParallel. The constraint dialog allows you to specify the constraint direction. The constraint will make the planes parallel.

Plane on Plane

Select a plane on both parts. The toolbar button adds the constraint planeCoincident. The constraint dialog allows you to specify a constraint direction and an offset between the planes. This offset can also be flipped. If the offset is zero, the constraint will make the planes coincident.

Plane Angular

Select a plane on both parts. The toolbar button adds the constraint angledPlanes. The constraint dialog allows you to specify an angle between the planes. The constraint will make the planes at first parallel and the set the specified angle.

Coincidence at Center of Mass

Select either a closed edge or a plane on both parts. The toolbar button adds the constraint centerOfMass. The constraint dialog allows you to specify an offset between the edges or planes. This offset can also be flipped. You can furthermore set the constraint direction and lock the rotation of the parts. If the offset is zero, the constraint will put the edges or planes into the same plane.

Subassemblies

An assembly can contain other assemblies. They are added like parts by pressing the toolbar button and selecting a *.FCStd file containing an assembly. Such subassemblies can also be edited like parts using the toolbar button . Please make sure for higher assembly stages that you update the assembly via the toolbar button when there were changes.

Constraint Handling

Possible constraints for a selection are displayed in the toolbar and the Constraint Tools dialog by enabling the corresponding buttons. The Constraint Tools dialog is opened via the toolbar button . It is intended to stay open to be able to add quickly several constraints to the assembly.

Existing constraints can be edited by selecting them in the model tree and then either double-clicking on it or using the toolbar button . This opens the Constraint Properties dialog.

Constraints can be deleted either by selecting them in the model tree and pressing Del or by selecting a part with constraints in the model tree and using the toolbar button .

All constraints can be resolved at any time with the toolbar button . If the toolbar button is turned on a resolve is automatically done after every edit of a constraint.

The toolbar button affects the constraint that was added most recently. It flips the constraint direction.

Part Lists

To create part lists of assemblies, the different parts of the assembly must get part info that can be read by A2plus. This is done by editing the part using the toolbar button . In the opened part press the toolbar button and a spreadsheet with the name #PARTINFO# is created.

The structure of the spreadsheet is like this:

Fill out the grey fields with info you have and want to have in the final parts list.

In the assembly or subassembly use the toolbar button . It will ask you if you want to iterate recursively over all subassemblies. Click on Yes. This creates a new spreadsheet with the name #PARTSLIST#. It contains the info from the different #PARTSINFO# spreadsheets of the parts in a list like this:

The position (POS) is automatically set according to the appearance of the parts in the model tree. The top level part will get POS 1.
The quantity (QTY) is automatically calculated from the assembly. If a parts is twice in the assembly it will get QTY 2.

If you have updated a part info you can refresh the parts list by pressing the toolbar button again.

For subassemblies you can also create an info spreadsheet using the toolbar button . When you create or update the parts list of the main assembly this info will be used if you click on No for the question if you want to iterate recursively over all subassemblies. Then the different parts are not in the parts list but only the subassemblies.

Special Features

Assembly Structure

The toolbar button creates an HTML file with the structure of your assembly. The file will by default be created in the folder of your assembly file. The structure looks like this one:

Degrees of Freedom

The button labels every part of the assembly with its degrees of freedom. Furthermore it outputs a list with all parts and their dependencies. The list is output into FreeCAD's widget Report view. If this widget is currently not visible, it can either be shown by right-clicking into an empty part of the FreeCAD toolbar area and then choosing it in the appearing context menu or with the menu View → Panels → Report view.
The degrees of freedom labels can be removed by clicking the button again.

Part Labels

The button labels every part of the assembly in the 3D view with its name. The part labels can be removed by clicking the button again

Shape of whole Assembly

Sometimes it is necessary to have the whole assembly combined as one shape. This shape can then for example be used for 3D printing in the Mesh workbench or for drawings in the TechDraw workbench. It is created using the toolbar button . The shape is by default not made visible. Use the same toolbar button to update the shape in case of changes in the assembly.

Preferences

The a2plus preferences can be accessed via FreeCAD's menu Edit → Preferences and there in the section A2plus. You can set the following options:

Default solving method

  • Use solving of partial systems
    The solver begins with a part that has the property Datafixed Position set to true and a part constrained to it. All other parts are not calculated. If a solution could be found, the next constrained part is added to the calculation and so on.
  • Use "magnetic" solver, solving all parts at once
    The solver tries to move all parts at once in direction to a part that has the property Datafixed Position set to true. Note that this will in most cases take more time for the calculation of a solution.
  • Force fixed position
    This sets the property Datafixed Position to true for all parts in the assembly. Then no calculation is actually performed since all parts will always be fixed to the positions where they were created.

Default solver behaviour

  • Solve automatically if a constraint property is changed
    The solver will automatically be started. The same as turning on the toolbar button .

Behaviour when updating imported parts

  • Recalculate imported parts before updating them
    All parts of the assembly, including subassemblies, will be opened in FreeCAD to be reconstructed using values from spreadsheets.
    This feature is designed to construct fully parametrically. Note: This feature is very experimental and not recommended for important projects.
    Known problems:
    • The assembly can be destroyed because of wrong references to topological names in parts
    • Master spreadsheets can get broken when they are edited while a referenced part file is already closed. This can crash FreeCAD.
  • Enable recursive update of imported parts
    Opens all subassemblies recursively to update them.
  • Use experimental topological naming
    While importing parts to the assembly an algorithm generates topological names for each subelement of the imported shape. The topological names are written into the Datamux Info. When an imported part needs to be updated, these topological names are used to update the subelements of the constraints. So assemblies get more robust against volatile subelement numbers of FreeCAD.
    Note: This increases file sizes and calculation time during import of parts. If topological naming should be used it has to be activated before the assembly is created.
  • Inherit per face transparency from parts and subassemblies
    Use colour and transparency settings from imported parts.
    Note: This feature is very experimental and not recommended for important projects.
  • Do not import invisible shapes
    This will hide invisible datum/construction shapes. Note: No constraints must be connected to datum/construction shapes in higher or other subassemblies. Otherwise you can break the assembly.
  • Use solid union for importing parts and subassemblies
    All imported parts will directly be put together as union.
    This feature is useful for FEM simulations or 3D-printing if only one solid is allowed. The alternative is to create a shape of the whole assembly later on.

User interface settings

  • Show constraints in toolbar
    If this option is not used, the toolbar buttons for the different constraints are not visible to save space in the toolbar. New constraints can still be set using the Constraint Tools dialog (toolbar button ).
  • Use native file manager of your OS
    If this option is used, you get the file dialog of your OS when selecting files for assemblies.

Storage of files

  • Use relative paths for imported parts
    Uses relative file paths to the part files.
  • Use absolute paths for imported parts
    Uses absolute file paths to the part files.
  • All files are in this project folder:
    All project files have to be in the specified folder. It doesn't matter if they are in subfolders of this folder. Note: No file is allowed to exist several times in the folder (e.g. in different subfolders).
    This option is helpful to work on different machines because then one only has to copy the project folder.

Troubleshooting

Sooner or later you will get the problem that A2plus cannot solve the constraints you set. To overcome this, there are different strategies:

Checking Constraint Direction

Sometimes constraints seem to be consistently defined but they can nevertheless not be solved. An example: Assume you have a planesParallel constraint set for two planes. Now you want to set for the same planes the planeCoincident constraint and A2plus cannot solve this. Then the constraint directions of planesParallel and planeCoincident are different. Use the same direction for both constraints to fix this.

Deleting Constraints

Most cases of unsolvable constraints occur directly when adding a new constraint. The solution is then to delete the constraint you added last. A2plus will propose this, too.

Sometimes the deletion strategy is the only one, for example when you edited a part in FreeCAD so that faces or edges connected to constraints are missing. You should then delete one constraint that is connected to the changed part at a time. Use the toolbar button after every deletion to see if you reached a solvable state.

When you got an assembly that can be solved, add step by step the constraints you need.

Moving Parts

In some cases the solver only needs better start values to solve the constraints. Take for example the case that you have an axle part and a wheel part. You add a axisCoincident constraint and get no info that the solver failed but the parts are not moved accordingly and in the Report view widget of FreeCAD you see "REACHED POS-ACCURACY :0.0". A solution for this is to move the parts closer to that position you like to get by the constraint.

Note: Assure that at least one part of the constraint has the property Datafixed Position set to false.

Setting the Tip Property

If you miss some features of your part after the import to an A2plus assembly, check the property DataTip.
A2plus imports bodies of parts with all their features up to the tip feature. This is sensible because setting the tip to a certain feature means that all features behind the tip should not appear in the final part. So if you miss a part feature in A2plus, open the part via the toolbar button , then select a body and look at its property DataTip. If the tip is not at the feature where you want it, right-click on the feature where the tip should be and choose Set tip. Finally save the part and reload the assembly using the toolbar button .

Repairing Assembly Tree

If you cannot see a clear reason why some constraints cannot be resolved, you can try to use the toolbar button . This will resolve all constraints and re-group then again under the different parts.

Avoiding Accented Characters

On some operating systems you can get problems if the file names or the file paths of parts or the assembly contain accented characters. Therefore avoid such characters and also special characters in general.

Fixing Position

This strategy is no longer necessary for assemblies created with A2plus 0.3.11 or newer because A2plus issues now a warning for missing fixed positions.

When you set a constraint between two parts and no part has the property Datafixed Position set to true or is connected by a constraint to a part with Datafixed Position set to true, the constraint cannot be solved. The same happens if both parts of the constraint have Datafixed Position set to true.

Then A2plus outputs the info about the failed solution, but sometimes you only see that the parts are not moved accordingly and in the Report view widget of FreeCAD you see "REACHED POS-ACCURACY :0.0". This means the solver finished without errors but it could actually not solve the constraints.

Therefore check that at least one of your parts in the assembly has Datafixed Position set to true. Then assure that you only set constraints to a part which is somehow connected to the fixed part. To visualise these dependencies, see section Assembly Structure.

Rotating Parts

This strategy is no longer necessary for assemblies created with A2plus 0.4.0 or newer because A2plus rotates the parts now automatically a bit in the background to get a sufficient start angle for the solver.

The solver often fails for the constraint angledPlanes if the two selected planes have currently an angle of 0° or 180°. (The parts are not moved accordingly and in the Report view widget of FreeCAD you see "REACHED POS-ACCURACY :0.0".) A solution for this is to rotate one part by a few degrees using FreeCAD's transform feature (right-click on the part in the model tree and select in the context menu Transform).

Note: Assure that at least one part of the constraint has the property Datafixed Position set to false.

Animation

A2plus offers animations via dragging and via Python scripts.

Dragging

Dragging animations are interactive since you trigger it by dragging a part of the assembly. To get these kind of animations:

  1. Fully constrain the part whose movement or rotation should be animated
  2. Click on the toolbar button . This enables the dragging mode.
  3. Click on the desired part in the assembly.
  4. Now you can move the mouse and the part will follow the movement of the mouse within the defined constraints.
  5. To end the dragging mode, left click in the assembly or press ESC.

Here is an example assembly to try out the dragging animation: A2p_example-for-dragging-animation.FCStd

This is the dragging animation using the example assembly:

Scripting

Despite the dragging mode offers nice interactive animations, they are sometimes not precise enough for screencasts or videos. Scripted animations have the advantage that they animate movements and rotations in a defined way. You can for example rotate a part by exactly 10° back and forth. The following examples use an assembly where a part should be rotated. If you try to animate this using the dragging mode, you will see how hard it is to get a back and forth rotation that you can e.g. show your boss in a presentation. With the interactive example script, however, this is an easy task.

A scripted animation works usually this way:

  1. The assembly is fully constrained
  2. The script changes a parameter, for example the position or rotation angle of a part
  3. After the parameter change, the assembly constraints are solved
  4. Step 2. and 3. are repeated to get the animation

It is also possible to change instead of a placement parameter a constraint, for example the distance between 2 planes.

Simple Script Example

The simplest way to script an animation is a non-interactive animation that follows a defined movement. Here is an example: First download this assembly file: A2p_animated-example.FCStd and also this Python script: A2p_animation-example-script.py.

This is the content of the script and the lines beginning with a '#' describe what the different script lines do:

# import libraries
import time, math, PySide
import A2plus.a2p_solversystem as a2p_solver

# we use steps of 1 degree
step = 1
# wait 1 ms between every step
timeout = 0.001
# initial angle is 0 degree
angle = 0
# we take the currently opened document
document = FreeCAD.activeDocument()
# we want later change the rotation angle of the part "star_wheel_001"
starWheel = document.getObject("star_wheel_001")
# define a progress dialog running from 0 to 360
progressDialog = PySide.QtGui.QProgressDialog(u"Animation progress", u"Stop", 0, 360)

# the while block is the main loop to change the angle and solve
# the assembly constraints subsequently
while angle < 360: # run this loop until we have one full turn (360 degrees)
    # increase the rotation angle
    angle += step
    # set the new angle to the progress dialog
    progressDialog.setValue(angle)
    # change the rotation angle of the part "star_wheel_001"
    starWheel.Placement.Rotation.Angle = math.radians(angle)
    # solve the constraints 
    a2p_solver.solveConstraints(document, useTransaction=True)
    # update the view after the solving ('Gui' stands for 'graphical user interface')
    FreeCADGui.updateGui()
    # bring the progress dialog to front
    PySide.QtGui.QWidget.raise_(progressDialog)
    # if 'Stop' was pressed in the dialog, exit the loop
    if progressDialog.wasCanceled():
        angle = 360
    # wait some time before performing the next step
    time.sleep(timeout)

To use the script to perform the animation, we must

  1. Open the assembly file in FreeCAD.
  2. Open the script file in FreeCAD.
  3. Click on the toolbar button to execute the script (also called macro).
  4. Change to the tab of the assembly to see the rotation.

To practice, just change something in the script and execute it afterwards. For example increase step to 5.

This is the result of the example animation:

Interactive Script Example

The first script example demonstrated how to create an animation without any user feedback. For most applications you need to interact with the animation. For example the interesting issue in the example is to see how the driving pins cross the center groove of the wheel. To have a closer look you might present this detail to your colleagues or boss. Therefore you need an interactive solution.

This can be done by using a custom animation dialog with a slider. By moving the slider you can set the rotation angle and therefore rotate back and forth at interesting position.

We use the same assembly file: A2p_animated-example.FCStd and this Python script: A2p_animation-example-script.py.

This is the content of the script to get the interactive animation dialog:

# import libraries
import time, math, PySide, sys
import FreeCAD.A2plus.a2p_solversystem as a2p_solver
from FreeCAD import Units
from PySide import QtCore, QtGui

# wait 1 ms after every calculation
timeout = 0.001
# we take the currently opened document
document = FreeCAD.activeDocument()
# we want later change the rotation angle of the part "star_wheel_001"
starWheel = document.getObject("star_wheel_001")

class AnimationDlg(QtGui.QWidget): # the animation dialog

    def __init__(self): # to initialize the dialog
        super(AnimationDlg, self).__init__()
        self.initUI()

    def initUI(self): # the definition of the dialog components
        self.setMinimumSize(self.minimumSizeHint()) # set the minimal dialog size to minimum
        self.setWindowTitle('Animation Dialog')
        # use a grid layout for the whole form
        self.mainLayout = QtGui.QGridLayout()
        self.lineNo = 0 # first dialog grid line
        # add description label
        DescriptionLabel = QtGui.QLabel(self)
        DescriptionLabel.setText("Change slider to change rotation angle")
        self.mainLayout.addWidget(DescriptionLabel,self.lineNo,0,1,4)
         # next dialog grid line
        self.lineNo += 1
        # add a label; there is no need for the "self." prefix because we don't want to change the label later
        LabelMin = QtGui.QLabel(self)
        LabelMin.setText("Min")
        LabelMin.setFixedHeight(32)
        self.mainLayout.addWidget(LabelMin,self.lineNo,0)
        # add a spin edit to define the slider minimum
        self.MinEdit = QtGui.QSpinBox(self)
        # get the angle unit as string
        self.MinEdit.setSuffix(" " + str(FreeCAD.Units.Quantity(1, FreeCAD.Units.Angle))[2:])
        self.MinEdit.setMaximum(999)
        self.MinEdit.setMinimum(0)
        self.MinEdit.setSingleStep(10)
        self.MinEdit.setValue(0)
        self.MinEdit.setFixedHeight(32)
        self.MinEdit.setToolTip("Minimal angle for the slider")
        QtCore.QObject.connect(self.MinEdit, QtCore.SIGNAL("valueChanged(int)"), self.setMinEdit)
        self.mainLayout.addWidget(self.MinEdit,self.lineNo,1)
        # add the slider
        self.slider = QtGui.QSlider(QtCore.Qt.Horizontal, self)
        self.slider.setRange(0, 360)
        self.slider.setValue(0)
        self.slider.setFixedHeight(32)
        self.slider.setToolTip("Move the slider to change the rotation angle")
        QtCore.QObject.connect(self.slider, QtCore.SIGNAL("sliderMoved(int)"), self.handleSliderValue)
        self.mainLayout.addWidget(self.slider,self.lineNo,2)
        # add a label
        LabelMax = QtGui.QLabel(self)
        LabelMax.setText("Max")
        LabelMax.setFixedHeight(32)
        self.mainLayout.addWidget(LabelMax,self.lineNo,3)
        # add a spin edit to define the slider maximum
        self.MaxEdit = QtGui.QSpinBox(self)
        # get the angle unit as string
        self.MaxEdit.setSuffix(" " + str(FreeCAD.Units.Quantity(1, FreeCAD.Units.Angle))[2:])
        self.MaxEdit.setMaximum(999)
        self.MaxEdit.setMinimum(1)
        self.MaxEdit.setSingleStep(10)
        self.MaxEdit.setValue(360)
        self.MaxEdit.setFixedHeight(32)
        self.MaxEdit.setToolTip("Maximal angle for the slider")
        QtCore.QObject.connect(self.MaxEdit, QtCore.SIGNAL("valueChanged(int)"), self.setMaxEdit)
        self.mainLayout.addWidget(self.MaxEdit,self.lineNo,4)
         # next dialog grid line
        self.lineNo += 1
        # add a spacer
        self.mainLayout.addItem(QtGui.QSpacerItem(10,10), 0, 0)
        # add a label
        LabelCurrent = QtGui.QLabel(self)
        LabelCurrent.setText("Current angle:")
        LabelCurrent.setFixedHeight(32)
        self.mainLayout.addWidget(LabelCurrent,self.lineNo,1)
        # output the current angle
        self.CurrentAngle = QtGui.QLineEdit(self)
        self.CurrentAngle.setText(str(0))
        self.CurrentAngle.setFixedHeight(32)
        self.CurrentAngle.setToolTip("Current rotation angle")
        self.CurrentAngle.isReadOnly()
        self.mainLayout.addWidget(self.CurrentAngle,self.lineNo,2)
        # add label for the unit
        LabelUnit = QtGui.QLabel(self)
        LabelUnit.setText("deg")
        LabelUnit.setFixedHeight(32)
        self.mainLayout.addWidget(LabelUnit,self.lineNo,3)
        # button to close the dialog
        self.Close = QtGui.QPushButton(self)
        self.Close.setText("Close")
        self.Close.setFixedHeight(32)
        self.Close.setToolTip("Closes the dialog")
        QtCore.QObject.connect(self.Close, QtCore.SIGNAL("clicked()"), self.CloseClicked)
        self.mainLayout.addWidget(self.Close,self.lineNo,4)
        # place the defined grid layout to the dialog
        self.setLayout(self.mainLayout)
        self.update()

    def handleSliderValue(self):
        # set slider value as angle
        starWheel.Placement.Rotation.Angle = math.radians(self.slider.value())
        # output current angle
        self.CurrentAngle.setText(str(self.slider.value()))
        # solve the constraints 
        a2p_solver.solveConstraints(document)
        # update the view after the solving ('Gui' stands for 'graphical user interface')
        FreeCADGui.updateGui()
        # wait some time, important to give time to perform calculations
        time.sleep(timeout)

    def setMinEdit(self):
        # assure that the minimum is samller than the maximum
        if self.MinEdit.value() >=  self.MaxEdit.value():
            self.MaxEdit.setValue(self.MinEdit.value() + 1)
        self.slider.setRange(self.MinEdit.value(), self.MaxEdit.value())

    def setMaxEdit(self):
        # assure that the minimum is samller than the maximum
        if self.MinEdit.value() >=  self.MaxEdit.value():
            self.MinEdit.setValue(self.MaxEdit.value() - 1)
        self.slider.setRange(self.MinEdit.value(), self.MaxEdit.value())

    def CloseClicked(self):
        AnimationDialog.close()

# create and show the defined dialog
AnimationDialog = AnimationDlg()
AnimationDialog.show()

# run this loop when the dialog is visible
while AnimationDialog.isVisible():
    # update the view; important to give the OS feedback the dialog is alive
    FreeCADGui.updateGui()
    # bring the dialog to front, so that the dialog is always visible
    QtGui.QWidget.raise_(AnimationDialog)
    # output slider value here too because during the calculation the slider might have been moved
    AnimationDialog.CurrentAngle.setText(str(AnimationDialog.slider.value()))

The dialog defined in the script looks like this:

Script Commands

To understand the script syntax better, here is some command info:

The command

starWheel.Placement.Rotation.Angle = math.radians(angle)

means, we change the placement property Rotation.Angle of the part get got previously as "starWheel". This property gets the angle as radian. The function radians() from the library math converts the angle from degree to radian.


The property Rotation.Angle uses the current placement axis of the part (in our example the x-axis). To rotate the part e.g. around the z-axis one can set the rotation axis (before calling the rotation command) using the command

starWheel.Placement.Rotation.Axis = FreeCAD.Vector(0,0,1)

Instead of rotating, parts can also be moved. To change for example the placement in y-direction of the wheel, the command would be

starWheel.Placement.Base.y = PositionShift

In this case we would not define the variable angle but PositionShift that we change on every loop run.
There are different ways to set the placement of a part. Some are documented here. Unfortunately there is no list with all possible placement commands.


The command

a2p_solver.solveConstraints(document, useTransaction=False/True)

is a A2plus-specific command. It solves the assembly constraints of the assembly we previously got as "document". The option useTransaction specifies if FreeCAD should store every change in the undo/redo stack. For large animations you might therefore set it to False.