Std DependencyGraph/de

Description
The Dependency graph displays the dependencies between objects in the active document as a graph. As opposed to the Model tree, objects are listed in reverse chronological order, with the first created object at the bottom.

It can be useful in analyzing a FreeCAD document and locating forks in a tree. The dependency graph layout will depend on which workbench was used to create the objects in the document. For example, in FreeCAD 0.16, a model exclusively made in the PartDesign workbench should display a linear dependency graph with a single vertical branch. A model made with Part operations will have many branches, but for a single part they will join up at the top after Boolean operations. If they don't, it means that they are separate objects.

The dependency graph is purely a visualization tool, therefore it cannot be edited; it automatically updates if changes are made to the model.



Installation
To use the Dependency graph, a third-party software named Graphviz needs to be installed first. If you do not have it pre-installed or it is installed in an unconventional location, FreeCAD will display the following dialogue:



Windows
Download the graphviz-2.xx.msi installer from the Graphviz Download page and launch it to install it.

Mac/OSX
You can install graphviz using Homebrew:

This installs the graphviz binaries under /usr/local/bin. Unfortunately we can't navigate directly there from the file dialog that comes up from FreeCAD → Tools → Dependency graph. When you get the file selection dialog use the keys Cmd+Shift+G to get an input field for the path. Enter

and confirm the input field and the file selection dialog.

In case the Graphviz binaries are installed in a non-standard location try to find the program with the command

It will output something like

And therefore you can tell FreeCAD to look in that directory.

Linux
On most Linux distributions (Debian/Ubuntu, Fedora, OpenSUSE), you just need to install the graphviz package from the repositories. However, similarly to MacOSX, in cases where the Graphviz binaries are installed in a non-standard location, try to find the program with the command:

It may output something like

And therefore you can point FreeCAD to look in that directory.

Configuration
You shouldn't need any configuration of FreeCAD preferences. If FreeCAD cannot find the utility "dot" (from the Graphviz package) then a dialog comes up and asks the user for its path: set the path to the folder that contains the "dot" executable, do not select the executable itself. FreeCAD then tries to start the utility again and in case it succeeds the value is written automatically to the user parameters.

How to use

 * 1) Go to the Tools → Dependency graph... menu
 * 2) A new tab titled Dependency graph opens over the main area of the FreeCAD window.
 * 3) Use the mouse scroll wheel to zoom in / zoom out.
 * 4) Use the horizontal slider at the bottom of the screen to pan the view sideways.

Save/Export
You can save/export the displayed dependency graph as an image file. While the Dependency graph tab is in the foreground:
 * Just choose File → Save As to save the graph as a picture (PNG/BMP/GIF/JPG), a vector graphic (SVG) or as a PDF document.
 * File → Export or Tools → Save picture will NOT work.

General principles

 * The graph shows objects in reverse chronological order, from the bottom to the top.
 * The direction of arrows showing dependencies should always point down, from the child object to the parent object. An arrow pointing up indicates a cyclic dependency, an issue that needs to be resolved.
 * A sketch that contains links to external geometry will have a number with an "x" suffix besides the arrow linking it to its parent, showing the number of external geometry linked in the sketch.
 * Objects can have dependencies to multiple parents. For example, for a model built in PartDesign, a Pocket may be linked to its Sketch and to the Pad feature that came before it.
 * Disallowed dependencies (for example, between a Draft/Part operation and an element inside a PartDesign Body) will show with a red arrow. This type of link usually shows a "Links go out of allowed scope" error in the report view.
 * Part container and PartDesign Body enclose their content inside a frame with a randomly colored background. Their Origin also enclose their content (standard planes and axes) in a frame.
 * Group is displayed as a single element linked to its content.

Limitations

 * The dependency graph cannot help with the topological naming problem. If a sketch switches faces of a feature after an edit, it is still linked to the feature; even if some features are broken, the dependency graph will remain unchanged.
 * A bug in v0.17/v0.18 causes a Body to disappear from the graph and its content to disseminate if a Part or Draft object is created from the Body. This otherwise does not affect the model.