AlternateRebar

Splits a group of reinforcements into two independent, interleaved groups at double the original spacing.

General Description

When a group of reinforcements needs a construction joint or a staggered splice, a single continuous set of bars at one spacing must become two sets of bars at twice the spacing, offset from each other by one bar position. AlternateRebar automates this: select a shape-driven group of reinforcements and the command creates a second, independent group and re-lays out both so together they still cover the original envelope, alternating between the two sets.

Key Features

• Splits a rebar set into two independent, host-attached rebar sets in a single command
• Preserves shape, hooks, and parameters on the new set
• Doubles the spacing on both resulting sets so they interleave correctly
• Handles both even and odd bar counts, including sets where the first or last bar is hidden

Requirements

• Works on shape-driven reinforcement sets only (Revit rebar created from a rebar shape, not free-form).
• All bars in the set must share the same length; sets with variable length distribution are rejected.

Usage Procedure

1. Open Alternate Rebar from the Structure panel on the Frata ribbon tab.
2. Follow the prompt: "Select the groups of reinforcements to alternate, then press Finish."
3. The command splits each selected set into two interleaved sets automatically — no further input needed. The split always happens after the first bar position, so the two resulting sets start offset by one position.

Recommendations

• Undo (Ctrl+Z) reverts the split, since the whole operation runs in a single transaction.
• If a set fails, none of the other selected sets are modified either — the transaction rolls back as a whole.

Frequently Asked Questions

I got the message "Only shape-driven groups of reinforcements can be alternated." Why? The selected reinforcement is free-form, not shape-driven. Alternate Rebar only works on sets created from a rebar shape.

I got the message "The selected group of reinforcements has variable length and cannot be alternated." Why? The bars in the set don't all share the same length. Alternate Rebar can only alternate sets with a uniform bar length.

Can I alternate several sets at once? Yes — select multiple sets before pressing Finish; each is processed independently within the same transaction.