Main Bar: Automate beam and slab reinforcement in Revit
BIMStudio's Main Bar plugin places primary longitudinal reinforcement in Revit beams and slabs automatically, cutting rebar modeling time by up to 90%.
BIMStudio Team · April 24, 2026 · 3 min read
Placing longitudinal reinforcement — the main bars — in beams and slabs is foundational structural work, but in Revit it is painfully repetitive. Each bar set requires defining the rebar shape, setting the hook direction, constraining to the correct cover, and repeating the process for top and bottom layers. Main Bar by BIMStudio automates all of this in a single operation.
What Main Bar does
Main Bar places primary longitudinal rebar in beams and slabs according to the parameters you specify. It handles bar sizing, spacing, cover, and hook placement — producing native Revit rebar that integrates with schedules, tags, and IFC exports.
Key capabilities:
- Beam and slab support — works with rectangular beams, T-beams, and floor slabs.
- Top and bottom layers — places reinforcement in both tension and compression zones.
- Bar spacing control — set exact spacing or a target number of bars per layer.
- Hook configurations — standard hooks at beam ends, customizable by angle and length.
- Multi-span aware — handles continuous beams with correct bar termination at supports.
- Batch placement — reinforce multiple elements in a single run.
How it works
- Select one or more beams or slab regions in the Revit model.
- Open Main Bar from the BIMStudio ribbon tab.
- Configure: bar diameter, number of layers, spacing, cover, and hook type.
- Click Place — the plugin generates all main reinforcement bars inside the selected elements.
- Review placement in a section or 3D view.
The bars are standard Revit Rebar objects. They show up in reinforcement schedules, can be tagged with rebar tags, and include correct bar mark information.
Why structural teams use Main Bar
Dramatic time savings
Modeling main reinforcement for a typical floor of beams takes a full day of manual work. Main Bar reduces that to under 30 minutes. Over a multi-story project, the plugin can save weeks of modeling effort.
Consistent bar placement
When bars are placed by hand, small inconsistencies compound: one beam gets 25mm cover, the next gets 30mm. Stirrup hooks face different directions. Main Bar enforces uniform rules across every element, producing shop-drawing-ready output from the start.
Better coordination
Rebar modeled in 3D participates in clash detection. MEP engineers can route services around actual bar positions instead of guessing from 2D details. This shifts coordination issues upstream where they are cheaper to resolve.
Typical use case
A structural engineer is working on a 10-story residential building. Each floor has approximately 30 beams. Manual rebar modeling would take:
- 30 beams x 45 min per beam = 22.5 hours per floor
- 10 floors = 225 hours = ~28 working days
With Main Bar:
- 30 beams x batch processing = ~20 minutes per floor
- 10 floors = ~3.3 hours total
The time freed up goes toward engineering review, detailing complex connections, and coordination — higher-value work.
Main Bar vs. manual rebar modeling
| Feature | Manual | Main Bar |
|---|---|---|
| Time per beam | 30–60 min | Seconds (batch) |
| Cover consistency | Varies | Uniform |
| Hook direction | Manual check needed | Pre-configured |
| Multi-span handling | Complex | Automatic |
| Schedule integration | Same | Same (native Rebar) |
Who benefits most
- Structural engineers modeling rebar for construction documents.
- BIM detailers producing shop-drawing-quality models.
- Design-build firms that need fast rebar quantities for bidding.
- Structural BIM managers looking to standardize rebar modeling practices across teams.
Get started
Main Bar is part of the free BIMStudio Revit plugin collection. Download it from our Revit Plugins page and start automating your beam and slab reinforcement today.