External workbenches

Introduction
Power users have extended FreeCAD with various custom workbenches and addons that are not integrated into the FreeCAD source code but can be added to an existing FreeCAD installation.

Most extensions can be installed from the Addon Manager, menu ; specific instructions are provided in each extension page.

General

 * Defeaturing provides tools to edit STEP models by removing selected features.
 * DynamicData allows creation of container objects for holding custom properties.
 * WebTools contains a series of tools to communicate with Web services from within FreeCAD.
 * Curves is a collection of tools to create and edit NURBS curves and surfaces.
 * Nurbs is a collection of scripts for managing freeform surfaces and curves.
 * Silk is a collection of NURBS surface modeling tools focused on low degree and seam continuity.
 * GDT is a collection of tools to add geometric dimensioning and tolerancing (GDT) labels in 2D and 3D technical drawings. It implements the standard ISO 16792.
 * InventorLoader is a workbench under construction designed to import Autodesk Inventor files. Currently only Parts (IPT) can be displayed, not assemblies (IAM) nor drawings (IDW).
 * CadQuery allows users to write Python scripts, and is tailored to those based on the CadQuery CAD scripting API. Script variables can be edited dynamically through the use of a parameter dialog.

Architecture and facilities

 * BIM aims to implement complete Building Information Modeling (BIM) tools and workflow in FreeCAD. It builds on top of the Arch Workbench.
 * Reinforcement augments the Arch Workbench with additional Arch Rebar tools.
 * Flamingo is a set of customized FreeCAD commands and objects that help speed-up the creation of frames and pipelines.
 * Civil Engineering is a proposed workbench that intends to combine and develop different tools of interest to civil engineers, including those working with road engineering, terrain topology and geographic data.

Assembly and animation
As of FreeCAD 0.18 there is no official assembly workbench. However, several external tools have been created or are in development to manipulate objects to produce assemblies.

assembly workbenches are generally incompatible with each other. If you create an assembly with one of them, you should not use another workbench to work with the same assembly. You should re-assemble the parts in the new workbench.


 * Animation Workbench can be used to simulate kinematics.
 * A2plus provides tools to create multi-part assemblies. It is a fork and extension of the older Assembly2 Workbench.
 * Assembly3 (github link) is in development and requires a forked version of FreeCAD with some core changes. It is the most complex solution and supports things like interactive kinematics.
 * Assembly4 (github link) is a solution based on the forked FreeCAD branch that Assembly3 uses. It does not work with constraints at all and focuses on building structures with Local Coordinate Systems (LCS). This is computationally friendly, and should allow for creating large assemblies with many parts. This is the newest of the assembly workbenches and is intended more as a demonstrator.
 * Manipulator is aimed at helping users in aligning, moving, rotating and measuring 3D objects through a friendly graphical interface.
 * WorkFeatures adds a wide range of helper objects such as alignment planes or axes, and tools to help you to position and align objects along those helper objects.

Engineering

 * Cfd (github link) brings the power of the OpenFoam solver to FreeCAD to perform computation fluid dynamics (CFD) simulations.
 * CfdOF (github link) is a fork of Cfd that focuses on ease of use; it is intended for people who are just starting in the world of CFD and OpenFoam.
 * EM Workbench provides a graphical interface for different solvers by FastFieldSolvers. At present it supports the 3D magneto-quasistatic impedance solver FastHenry. Support for the 3D electrostatic capacitance solver FasterCap is ongoing.
 * KicadStepUp is aimed at helping both KiCad and FreeCAD users in collaborating with electrical (ECAD) and mechanical (MCAD) design.
 * LCInterlocking (github link) tools to create parts for laser-cutters. Add tabs and hinges. Export to SVG.
 * SheetMetal provides tools to design and unfold sheet metal parts.

Deprecated extensions

 * Drawing Dimensioning adds powerful dimensioning and annotation tools to the Drawing Workbench. It was deprecated in FreeCAD 0.17. Consider using TechDraw Workbench instead.
 * Assembly2 provides tools to create multi-part assemblies. It is unmaintained since 2016. Consider using A2plus instead.

Missing documentation

 * Bolts
 * EaglePCB_2_FreeCAD
 * Gears
 * FreeCAD-CuraEngine (this addon is unmaintained since 2014 and no longer works with recent versions of Cura engine.)
 * Lattice2
 * Exploded Animation
 * Fasteners
 * GeoData
 * Persistent toolbars
 * Retr3D
 * Timber