A beam is the best member to learn detailing on, because it gathers all three families of steel: longitudinal bars for bending, stirrups for shear, and secondary bars. Get one of the three wrong and the beam fails in a different way each time.
Beam reinforcement in Revit 2027 is done with the Rebar command on the Concrete tab, in a view whose cut plane passes through the beam. This article walks one real beam from a set of drawings: read the detail, start the command, pick a bar shape, place the longitudinal bars and then the stirrups, set spacing and hooks, and finally propagate the whole cage onto identical beams. For the full modelling and documentation workflow, the Institute runs a Revit Structure course.
Where the bars sit in a beam, and why
Three rules of detailing decide most of a simple beam drawing.
The bottom longitudinal bars run the whole length, because the sagging moment peaks at mid-span and stretches the bottom fibre. The top longitudinal bars are added over the supports, because the hogging moment stretches the top fibre exactly where the beam sits on a column. And the stirrups are closer together at both ends and wider apart in the middle, because shear peaks at the supports.
The beam used here is DX1.1 of a four-storey building, 300x500 in section, clear span 3370. The detail drawing shows all three rules: stirrups at 100 centres over the two 845 zones at the ends, at 200 centres over the 1685 middle zone, three Ø18 bars running the full soffit and two pairs of Ø18 over the supports.
The numbers for any given beam come from the designer, not from habit. Revit keeps the cover right, computes the bar lengths and produces the schedule; the analysis stays outside the software.
The file, the views and the drawing to read first
Step 1 — Open a view that cuts through the beam
Reinforcement only appears in a view whose cut plane passes through its host. Open a plan whose cut plane misses the beam and the bars stay invisible, even though they are in the model.
So the first job is a section along the beam plus a few cross sections where the reinforcement changes; see the article on sections in Revit. The beam itself has to exist first, see beams in Revit, and the file needs its bar diameters and cover declared, see rebar settings in Revit.
Step 2 — Read the tags and the stirrup zones on the long section
The tag 10 Ø8 a100 reads as ten 8 mm bars at 100 mm centres. The number in the circle is the bar mark, matching the schedule and the cross section. The dimension string along the top gives the zones 220, 580, 845, 1685, 845, 580, 220, which are the boundaries between close and wide stirrup spacing. Reading it tells you the job needs six bar sets: three stirrup sets, one bottom set and two top sets.
This article is part of the Institute's Revit Structure series.
When the seven Reinforcement buttons are live
Step 3 — Check the seven buttons before blaming the software
The Reinforcement panel of the Concrete tab holds seven buttons: Rebar, Path, Morphed, Area, Fabric Area, Fabric Sheet and Cover. They are not always available.
A sheet holds no members, so there is nothing to host a bar. Open a structural plan and the picture changes completely.
In a 3D view, release 2027.2 greys out exactly one button.
When a button is dim, check in order: are you on a sheet, are you in a 3D view, have you selected the host. Those three questions cover almost every case.
How to draw beam rebar in Revit: the Rebar command and its options
Step 4 — Start Rebar and read the six option panels
Click Rebar on the Reinforcement panel. The ribbon switches to the Modify | Place Rebar contextual tab.
| Panel | What it decides |
|---|---|
| Family | Load Shapes brings in more bar shapes, Shape Browser opens the shape picker |
| Placement Methods | Expand to Host fills the host member, By Two Points places between two clicks, Sketch draws freely |
| Placement Plane | The bar sits on the work plane, on the near cover face or on the far cover face |
| Placement Orientation | The bar runs parallel to the work plane, parallel to the cover or perpendicular to it |
| Set Type | Varying Rebar Set builds a set whose bars change size along the run |
| Show Tooltip | Turns the prompt that follows the cursor on and off |
The three middle panels decide where the bar sits and which way it turns, and the result depends on all three at once. Autodesk's Place Rebar page describes the two main placement methods and the Show Tooltip panel of this release.
With Show Help Tooltip on, a prompt follows the cursor while you place: the space bar rotates or flips the bar, [ and ] cycle through the orientation options, and holding Shift locks the bar orientation to a face.
Step 5 — Pick a bar shape in the Rebar Shape Browser
Click Shape Browser and Revit opens a panel down the right edge of the screen.
The panel lists every shape in the project with a thumbnail: BS_M_T1 is a closed rectangular stirrup, M_00 a straight bar, while M_17A and the Rebar Shape entries are various bends. Picking the shape before drawing is the fastest way to get the right bar.
Place the main bars first, then the stirrups in Revit
Step 6 — Place the main bars with Expand to Host
Pick the M_00 shape, click Expand to Host on the Placement Methods panel, then hover over the beam. Revit highlights the host and names it next to the cursor, as Structural Framing : M_Concrete-Rectangular Beam : 300500*. Only click once that line appears; until then there is no host to attach the bar to.
The direction of the main bars is chosen on the Placement Orientation panel, and can still be cycled while placing with the [ and ] keys. Place the bottom layer first and the top layer second, each as its own set so they can be edited independently.
Step 7 — Set the bar count with Layout Rule Fixed Number
A longitudinal set is defined by a count, not by a spacing.
The bottom set of beam DX1.1 reads Style Standard, Shape M_00, Layout Rule Fixed Number with Quantity 3. The Partition box holds DX1.1, which groups the steel by member in the schedule. The bar length is 4700.0 mm and the set weighs 28.16 kg.
Step 8 — Place the stirrups perpendicular to the cover
Switch the shape to BS_M_T1 and carry on. A stirrups in revit ring has to lie in a plane that cuts across the beam axis, so its orientation differs from the longitudinal bars. The surest check is to place one and look: if the new bar does not lie in the plane of the open view, Revit says so at once with None of the created elements are visible. Undo, change the orientation and place again.
Place three separate stirrup sets, one for each zone: two at the supports and one at mid-span. Splitting them now means changing one zone later does not drag the other two along.
Step 9 — Set the stirrup spacing with Maximum Spacing
For stirrups in revit, choose Maximum Spacing in the Layout Rule box and type the spacing.
The mid-span set reads Spacing 200.0 mm, while Quantity 9 is greyed out because Revit works it out from the spacing and the length of the zone. The engineer states that stirrups must not exceed 200 centres; Revit does the counting. Lengthen the beam and the count follows without any editing.
Layout Rule has five values: Single, Fixed Number, Maximum Spacing, Number With Spacing and Minimum Clear Spacing.
Reading a bar set back, and the tools for rebar in revit
Step 10 — Read the Construction group of a set
Select a bar and the Properties palette tells you everything about the set it belongs to.
The stirrup set reads Style Stirrup / Tie, Stirrup/Tie Attachment Interior Face of Cover, Shape BS_M_T1, Rebar Number 4 and Schedule Mark 2. Those last two are the numbers inside the circles on the drawing tags.
Step 11 — Read the weight and the length of the set
Scroll the Properties palette down to the Structural group. The mid-span stirrup set has Reinforcement Volume 610.73 cm³ and Reinforcement Mass 4.79 kg. The Dimensions group gives Bar Length 1351.4 mm with its rounded value beside it, and Total Bar Length 12150 mm for the whole set.
Step 12 — Choose the hooks at each end
Four boxes decide the anchorage: Start of Bar, Hook At Start, End of Bar and Hook At End. The stirrups of beam DX1.1 use Hook at both ends with the Stirrup Seismic - 135 degree type. The bottom longitudinal set uses None at both ends, because it anchors by embedment into the column rather than by a hook.
The length of each hook type is declared on the bar type, in the Rebar Hook Lengths dialog. Change it there and every bar of that type follows.
Step 13 — Work with the Modify | Structural Rebar tab
Select a bar and the ribbon shows a contextual tab with eight panels.
The Presentation panel chooses whether the first bar, the last bar or all of them are drawn. Constraints edits how each end of the bar is tied to a face of the host. Customization carries Edit Bars, which breaks a set into individual bars, and Symbol carries Bending Detail, which generates the bar bending diagram.
One thing measured on release 2027.2: the Presentation panel and the Bending Detail button only appear in a view with a cut plane, never in a 3D view.
Step 14 — Copy the cage onto identical beams with Propagate Rebar
Once one beam is detailed, select its bar sets, click Propagate Rebar and pick the beams that match; Revit copies the lot across. In a multi-storey building with typical beams, this is the correct way to repeat reinforcement, not copy and paste.
Step 15 — Check the result on a cross section and in 3D
A long section is not enough. Cut across the beam where the reinforcement changes to see whether the bars really sit in the right layer.
Last comes a 3D view kept purely for self-checking. It exposes three faults a flat section hides: column bars cut short at the beam face, beam bars driven straight through column bars, and stirrups forgotten inside the joint. The hardest case is a beam that changes direction, such as a stair stringer.
What a rebar add-in does that stock Revit does by hand
People really do search for rebar tools, so it is worth being plain about it. Four packages are still published: SOFiSTiK Reinforcement, Naviate Rebar from Symetri, CADS Rebar Extensions for Revit and GRAITEC PowerPack for Revit. By their makers' own descriptions they automate two things.
The first is generating a whole cage for a beam, column, footing or pile cap from one parameter dialog, applying it across many members of a kind, and updating it when the section changes. The second is producing views and schedules, tagging bars in bulk and exporting a file for a bar bending machine.
Two things need saying. No product called "Autodesk Rebar Extension" is published any more. And no add-in works properly until the file has its diameters, cover and rounding declared.
When Revit will not play along
| What you see | Why | What to do |
|---|---|---|
| Bars placed but nothing shows on the section | The cut plane of the view misses the beam | Fix the view range, or cut a new section through the beam |
| All seven Reinforcement buttons greyed | You are on a sheet | Open a plan, a section or a 3D view |
| A click on the beam creates no bar | The cursor has not caught the host yet | Hover slowly until the member highlights and names itself, then click |
| Revit warns None of the created elements are visible | The new bar does not lie in the plane of the open view | Undo, change Placement Orientation and place again |
| Quantity is greyed out and will not accept a number | Layout Rule is on Maximum Spacing, so Revit counts | Switch to Fixed Number to type a count |
| The drawing is choked with stirrup lines | The set is drawing every bar | Use the Presentation panel to show the first and last bar only |
| Editing one bar changes the whole set | A set is still a single element | Click Edit Bars on the Customization panel to break it |
Six things people get wrong
| What you hear | What the 2027 release actually does | |
|---|---|---|
| The Rebar command is on the Structure tab | Release 2027 puts it on the Concrete tab, Reinforcement panel | |
| Placement options are set on the Options Bar | They sit on the six panels of the Modify \ | Place Rebar tab |
| You cannot place reinforcement in a 3D view | Only Fabric Sheet is greyed; the four bar tools still work | |
| Stirrups have to be counted and typed in | Maximum Spacing lets Revit count them from the real length | |
| The bar properties read Reinforcement Weight | Release 2027.2 reads Reinforcement Mass | |
| Repeating reinforcement means copy and paste | Propagate Rebar copies a set onto the members that match |
In short, beam reinforcement in revit is a short loop: open a view that cuts the beam, pick a shape, place the longitudinal bars with Fixed Number, place the stirrups with Maximum Spacing, set the hooks, then propagate. With beams done, slabs, columns and footings follow.
Frequently asked questions
Longitudinal bars first or stirrups first?
Longitudinal first is easier to snap, because stirrups attach to the inside face of the cover rather than to the bars. The order does not change the result, only the amount of rework.
Why is Quantity greyed out?
Because Layout Rule is on Maximum Spacing and Revit derives the count from the spacing and the length. Switch to Fixed Number to type a count.
Which hook belongs on a stirrup?
The sample model uses Stirrup Seismic at both ends, a 135 degree hook. The length of each hook type is declared on the bar type, in the Rebar Hook Lengths dialog.
How do I detail a whole floor without repeating myself?
Detail one beam, then use Propagate Rebar on the beams that match. Beams of another section or span have to be done separately.
Can a full drawing set be produced without an add-in?
Yes. Stock Revit builds the cage, the sections, the tags and the schedules. An add-in shortens the repetitive part; it does not unlock work the base product cannot do.