Add Button to FEM Toolbar Tutorial

From FreeCAD Documentation
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Time to complete
60 min
FreeCAD version
Example files
See also


The FEM workbench has toolbars and menus. This tutorial shows how to add a test button to a toolbar. It also shows how to add a menu item to a menu.

The task can be split into four parts:

  • Create a new icon file.
  • Register the new icon file. Modification needed to src/Mod/Fem/Gui/Resources/Fem.qrc
  • Create a new command class. Modification needed to src/Mod/Fem/femcommands/
  • Add new command to workbench. Modification needed to src/Mod/Fem/Gui/Workbench.cpp

Create a new icon file

For the button, we need an icon file. You can use any of your favorite tools to create it, but it must be in the SVG format. Here we will use the FEM_testButton.svg file as an example.

It must be placed in: src/Mod/Fem/Gui/Resources/icons/.

Register the new icon file

The new SVG icon file has to be registered for the GUI button by inserting it in src/Mod/Fem/Gui/Resources/Fem.qrc:


Create a new command class

A new command class has to be added to the src/Mod/Fem/femcommands/ module.

Just copy/paste an existing command, then adjust the icon, menu text and tool-tip in __init__(self):

class _testButton(CommandManager):
    "The FEM_testButton command definition"

    def __init__(self):
        super(_testButton, self).__init__()
        self.menuetext = "test Button"
        self.tooltip = "This is a test button"
        self.is_active = "always"
        #self.do_activated = "add_obj_on_gui_selobj_noset_edit"

Don't forget to register the command at the bottom of the module file with the addCommand(...) method:


Note: Please see this discussion thread in the forum if icons are involved.

Add new command to workbench

We will add the new command to both the solve toolbar and the solve menu.

Search for the following code snippet in /Gui/Workbench.cpp and add the new command:

Gui::ToolBarItem* solve = new Gui::ToolBarItem(root);
     *solve << "FEM_SolverCalculixCxxtools"
            << "FEM_SolverCalculiX"
            << "FEM_SolverElmer"
+           << "FEM_testButton"
            << "Separator"

To add the command to the solve menu of the FEM workbench, search for the following code snippet in Workbench.cpp:

Gui::MenuItem* solve = new Gui::MenuItem;
    root->insertItem(item, solve);
    *solve << "FEM_SolverCalculixCxxtools"
           << "FEM_SolverCalculiX"
           << "FEM_SolverElmer"
           << "FEM_SolverZ88"
+          << "FEM_testButton"
           << "Separator"

Result: You should have just successfully added a test button to a FEM workbench toolbar and menu. Now, you can compile FreeCAD and test your new button.