FreeCAD, like many modern design applications such as Revit or CATIA, is based on the concept of Workbench. A workbench can be considered as a set of tools specially grouped for a certain task. In a traditional furniture workshop, you would have a work table for the person who works with wood, another one for the one who works with metal pieces, and maybe a third one for the guy who mounts all the pieces together.
In FreeCAD, the same concept applies. Tools are grouped into workbenches according to the tasks they are related to.
When you switch from one workbench to another, the tools available on the interface change. Toolbars, command bars and possibly other parts of the interface switch to the new workbench, but the contents of your scene doesn't change. You could, for example, start drawing 2D shapes with the Draft Workbench, then work further on them with the Part Workbench.
Note that sometimes a Workbench is referred to as a Module. However, Workbenches and Modules are different entities. A Module is any extension of FreeCAD, while a Workbench is a special GUI configuration that groups some toolbars and menus. Usually every Module contains its own Workbench, hence the cross-use of the name.
The following workbenches are available on every FreeCAD installation:
- The Arch Module for working with architectural elements.
- The Assembly Module for working with multiple shapes, multiple documents, multiple files, multiple relationships...
- The Complete Workbench hold all commands and features from all the modules and workbenches which met certain quality criteria.
- The Draft Workbench contains 2D tools and basic 2D and 3D CAD operations.
- The Drawing workbench for displaying your 3D work on a 2D sheet.
- The FEM Module provides Finite Element Analysis (FEA) workflow.
- The Image Module for working with bitmap images.
- The Inspection Module is made to give you specific tools for examination of shapes. It is still in development.
- The Mesh Module for working with triangulated meshes.
- The OpenSCAD Module for interoperability with OpenSCAD and repairing CSG model history.
- The Part Module for working with CAD parts.
- The Part Design Workbench for building Part shapes from sketches.
- The Path Workbench is used to produce G-Code instructions. It is still in early stages of development. Only v 0.16
- The Plot Workbench The Plot module allows to edit and save output plots created from other modules and tools.
- The Points Module for working with point clouds.
- The Raytracing Module for working with ray-tracing (rendering)
- The Reverse Engineering Module is intended to give you specific tools to convert shapes/solids/meshes into parametric FreeCAD-compatible features. It is still in development.
- The Robot Module for studying robot movements.
- The Ship Workbench FreeCAD-Ship works over Ship entities, that must be created on top of provided geometry.
- The Sketcher Module for working with geometry-constrained sketches.
- The Spreadsheet Workbench for creating and manipulating spreadsheet data.
- The Start Center allows you to quickly jump to one of the most common workbenches.
- The TechDraw Workbench is the more advanced and feature-rich successor of Drawing
- The Test framework is for debugging FreeCAD.
- The Web Module provides you with a browser window instead of the 3D-View within FreeCAD.
FreeCAD workbenches are easy to program in Python, there are therefore many people developing additional workbenches outside of the FreeCAD codebase. The External workbenches page has some information and tutorials about some of them, and the FreeCAD Addons project aims at gathering them and making them easily installable from within FreeCAD.
New workbenches are in development, stay tuned!