Slab Rebar Classic — bar kinds and point-based layout
The Slab Rebar Classic entry is BimSpeedRebarSlabClassic.Commands.RebarTools.SlabRebarCmd. Its editor and workflow differ from Slab Rebar 2.0. The entry initializes Classic context, checks authorization and ensures content before opening the editor.
Choose the diagram and understand the picking sequence
- Open a view where the Structural Floor's top face is accessible. Click the large diagram to open the shape library, select a shape and return to the main editor. Library Bottom/Top Layer captions do not replace checking the current Above/Below position setting.
- Choose the actual bar type/spacing, rounding and three cover inputs. Choose X/Y or Other direction and inspect the diagram before Draw. Rounding applies to extensions calculated from L/4 or L/5 spans; it does not change spacing or round every Bar Length. Inspect actual clear cover on the generated bar/section rather than relying only on the input label.
- Following the slab shape clips lines to the supported Floor solid/boundary, including openings. In point-based placement, P1→P2 defines the bar line and P3→P4 the distribution range. X/Y requires compatible bar/distribution directions; mismatched picks can prompt a warning or direction change. Other uses the chosen direction. Follow the prompts rather than picking four arbitrary points.
- Extension-dependent kinds may request P5/P6 for a span. With Bar length checked, enter the displayed EL values; otherwise use the span editor with 1/4 or 1/5. Reselect repicks the span; OK accepts extension values without generating bars. Esc cancels the current picking operation.
- Close the editor and inspect native Rebar sets in 3D/plan: Host, shape, Quantity, layout rule, actual spacing and length. Draw symbol/Draw spreading rebar enable 2D graphics in supported plans and may be disabled in 3D. There is no Tag/Plans picker in the Classic main window.
Which shapes enable L1/L2 or extension?
| Library diagram | L1/L2 | EL 1/EL 2 and Bar length |
|---|---|---|
| Bottom hook | Disabled | Disabled |
| Bottom straight 1 | Disabled | Disabled |
| Bottom straight 2 | Disabled | EL 2; direct Bar length or span editor |
| Bottom straight 3 | Disabled | EL 1+EL 2; direct Bar length or two-sided span editor |
| Bottom straight 4 | Disabled | Disabled |
| Bottom hat | Enabled | Disabled |
| Top hat 1 | Enabled | Disabled |
| Top hat 2 | Enabled | EL 2; Bar length/span editor |
| Top hat 3 | Enabled | EL 1+EL 2; Bar length/two-sided editor |
| Top straight | Disabled | Disabled |
| Two layers | Enabled | Disabled |
Numbers 1–4 identify diagrams within each group; thumbnail captions may only say Layer. Gray inputs are unavailable for that kind rather than missing mandatory data. Diagram L1/L2 differ from span-derived extension. A 4000 mm span gives 1000/800 mm for 1/4 and 1/5; a 5000 mm span gives 1250/1000 mm before the selected rounding. These are software extension calculations, not a designed development length.
Maximum versus actual spacing and later edits
Maximum spacing chooses positions so actual spacing does not exceed the limit; inspect native Quantity/spacing. Number with spacing uses a different layout rule. Special-slab single-bar totals cannot be substituted for Classic set quantities. Try 200→250 mm to reduce density, then return to 200 mm and inspect; only operations explicitly reported in the runtime evidence below have been tested.
Settings edits do not automatically update existing sets. Save a separate model before another Draw, distinguish old/new sets and use Undo when needed; Classic does not implicitly share special-slab ownership/update behavior. The title-bar X closes and stores Classic configuration; Ctrl+S saves the RVT.
Workflow
Open a suitable view, choose a diagram/bar kind, diameter/pitch/covers, face and direction. Run requests host/points and distribution according to the kind. Inspect the diagram and view before finishing. Verify actual Host, shape, Quantity, pitch and cover separately from annotations.
Controls
| Control / setting | Unit, condition, effect and verification |
|---|---|
Diameter / Spacing / Rounding | Actual project bar type; spacing is shown in mm with internal feet conversion; rounding is an mm increment for span-derived extensions. Options are1,5,10,15,20,25,30,35,40,45,50,55,60,65,70,80,90,100,150,200. Check Extension length after choosing a ratio; a straight Bar Length need not be a multiple of this increment. |
Concrete cover / Side / Top / Bottom | Side/top/bottom cover in mm. IsAbove and bar kind affect elevation; inspect sections. |
Following the slab shape | Clip against the slab solid; boundaries/holes can split a line into fragments. The hidden Rebar area checkbox is not a visible user control. |
Position of bars / Above-Below | Choose top/bottom placement for the relevant bar kind; this does not automatically generate both full mats. |
Direction | Direction choices affect bar lines/distribution derived from picked points. Review the diagram before running. |
Bar kind / shape selector | Choose among 11 kinds: bottom hook, bottom straight 1–4, bottom hat, top hat 1–3, top straight and two layers. Return to main; v 2 settings do not apply. |
L1 / L2 / ExtensionLength1 / ExtensionLength2 | Lengths in mm follow the selected shape. Extension can derive from the picked span and L/4 or L/5; these fields are not all anchorage lengths. |
L/4 / L/5; picked span | Choose each side’s ratio and verify the computed extension against the picked span. |
Draw symbol / Draw spreading rebar | Enable symbol/distribution graphics in a supported plan context. There is no Tag/Plans picker in the main Classic window.2D symbols do not prove native Rebar geometry. |
Number with spacing | Controls set distribution by number/pitch, unlike single bars in the special-slab modules. Inspect actual set Quantity and spacing. |
Draw / title-bar X | Draw enters host/point picking for the chosen kind; Esc cancels picking. The title-bar X closes the editor and stores Classic configuration; Ctrl+S saves the RVT separately. |
Additional controls and visibility
| Control | Condition and effect |
|---|---|
Bar length / EL1 / EL2 | Bar length is enabled only for applicable kinds. Check it to enter the required EL 1/EL 2 fields. Their visibility follows the diagram; otherwise a one/two-side editor can follow span picking. |
Extension editor / Existing span length / Span length / 1/4,1/5 / Extension length / Reselect / OK | Select a previous span or enter its length, choose each side’s ratio and verify the calculated extension. Reselect hides the editor for P5/P6 picking. OK accepts values; it does not itself generate steel. |
Maximum spacing / Number with spacing | Maximum spacing uses a pitch limit; Number with spacing uses number/pitch layout. Inspect actual Quantity/Spacing and end positions rather than dividing length by pitch alone. |
Draw symbol / Draw spreading rebar (enablement) | Enabled only in a suitable view/context, normally a ViewPlan. Pick the Structural Floor’s top face. Run temporarily hides steel and restores Temporary Hide/Isolate after picking. |
Evidence scope
Installed package 2026.10.23.2046 on Revit 2024 ran the production point writer on an existing project Floor: one set,15 positions, actual spacing 200 mm, type 10-A-II and 1490 mm Bar Length per position. Points were supplied through the harness; full entry/interactive picking remains untested. The private project RVT is not a public download.
Check cover before using the result: in this D10 example, a 30 mm bottom-cover input produced 25 mm measured clear cover to the bar outside. Successful creation does not establish compliant cover. Open a perpendicular section, read the actual diameter and measure concrete face→bar outside; centre depth is separate from clear cover. Keep a mismatching result subject to engineering correction; this is not a conforming detailing example to copy.