Arch Rebar

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Arch Rebar.svg Arch Rebar

Menu location
Arch → Rebar
Default shortcut
Introduced in version
See also
Arch Structure


The Arch Rebar tool allows you to place reinforcing bars inside Arch Structure objects.

Rebar objects are based on 2D profiles such as Draft objects and Sketches, that must be drawn on a face of the structural object. After creation you can adjust the properties of the rebar, including the number and diameter of the bars, and the offset distance between them and the faces of the structural element.

Arch Rebar example.jpg

Structural object with two sketches drawn on its faces, which are then turned into two sets of rebar objects

Extension available

The Rebar tool is enhanced by the Reinforcement Addon, which is installed by the Addon Manager. The additional rebar types available with the addon are:

How to use

  1. Create an Arch Structure element.
  2. Switch to the Sketcher Workbench.
  3. Select one face of the structural element.
  4. Press the Sketcher NewSketch.svg New Sketch button to start a new sketch on the selected face.
  5. Draw the diagram of your bar.
  6. Press the Sketcher LeaveSketch.svg Leave Sketch button to finish.
  7. Switch back to the Arch Workbench.
  8. Select the sketch you just drew.
  9. Press the Arch Rebar.svg Arch Rebar button, or press R then B keys.
  10. Adjust the desired properties (your rebar might not appear immediately, if some of the properties create an impossible situation, such as the bar diameter being 0, or the offset distances being bigger than the length of the structural element).


  • Rebars share the common properties and behaviours of all Arch Components
  • The rounding value is expressed in times the diameter. If your bar has a diameter of 5mm, a rounding value of 3 will create rounding at angles with a radius of 15mm.
  • Default values for new rebars can be set in the Arch preferences settings.
  • If a direction vector is not specified, the direction and distance along which the bars will spread is calculated automatically from the host structural object, by taking the normal direction of the base sketch, and taking its intersection with the structural object. If you specify a direction vector, the length of that vector will also be taken into account.
  • The spacing value is calculated from the current amount of bars, and represents the distance between the axes of each bar. You must therefore subtract the bar diameter to obtain the size of the free space between bars.


  • DATAAmount: The amount of bars.
  • DATADiameter: The diameter of the bars.
  • DATADirection: The direction (and length) along which the bars must spread. If the value is (0,0,0), the direction is calculated automatically from the host structural object.
  • DATAOffset Start: The offset distance between the border of the structural object and the first bar.
  • DATAOffset End: The offset distance between the border of the structural object and the last bar.
  • DATARounding: A rounding value to be applied to the corners of the bars, expressed in times the diameter.
  • DATASpacing: The distance between the axes of each bar.


See also: Arch API and FreeCAD Scripting Basics.

The Rebar tool can be used in macros and from the Python console by using the following function:

makeRebar (structure,sketch,[diameter],[amount],[offset])
  • Adds a Reinforcing Bar object to the given structural object, using the given sketch as profile.
  • If no diameter, amount or offset value is given, the default values from the Arch preferences settings are applied.
  • Returns the new Rebar object.


import FreeCAD, Arch, Sketcher, PArt
struct = Arch.makeStructure(1,1,3)
sketch = FreeCAD.ActiveDocument.addObject('Sketcher::SketchObject','Sketch')
sketch.Support = (struct,["Face6"])