Table of Contents

Joist Girder Weight

Automatically estimate and update weight values for joist girder elements in your Revit model. This tool calculates approximate weights based on span, depth, number of panel points, and loading conditions—saving you time during design development and helping ensure your models reflect realistic structural weights.

What is Joist Girder Weight?

Joist Girder Weight is a calculation tool that estimates the self-weight of joist girder elements and writes that value directly to a weight parameter on each element. The tool uses industry-standard moment-based formulas to approximate joist girder weights based on your design parameters.

The tool can run manually when you click the ribbon button, or automatically in the background whenever you switch views—keeping your weight values current as your design evolves.

When to Use

Scenario Description
Early design development Get realistic weight estimates before final joist girder selection
Load takeoffs Ensure self-weight values are populated for gravity load calculations
Model audits Verify all joist girders have weight parameters filled in
Design changes Update weights after modifying spans, depths, or loading
Before documentation Confirm weight schedules show accurate values

Quick Start

  1. Open a Revit model containing joist girder framing elements
  2. Ensure your joist girder families have the required parameters (see Family Requirements below)
  3. Go to the DB Tools ribbon tab
  4. Click Update Joist Girder Weights
  5. The tool processes all joist girders in the model and updates their weight parameters

That's it! Check your joist girder schedules to confirm the weight values have been populated.

User Interface

Ribbon Button

Location: DB Tools tab

Button Name: Update Joist Girder Weights

What it does: Scans your entire model for joist girder elements and calculates/updates the weight parameter for each one. A toast-style notification appears when processing is complete.

Settings

Auto-Update

When enabled, the tool automatically recalculates joist girder weights whenever you activate a different view. This keeps weight values current without manual intervention.

To change this setting: Access DB Tools settings through the ribbon. Toggle the auto-update option for Joist Girder Weight.

Note: If you're experiencing performance issues with large models, consider disabling auto-update and running the tool manually when needed.

Regex Pattern Configuration

The tool uses four regex patterns to identify joist girders and classify their load parameters:

Family/Type Name Pattern

Regex pattern to match joist girder family/type names.

Default: ^(?:(?:[BV]?G)|Vulcraft) Joist Girder$

Matches:

  • G Joist Girder
  • BG Joist Girder
  • VG Joist Girder
  • Vulcraft Joist Girder

Dead Load Pattern

Regex pattern to identify dead load parameters.

Default: (?:^DL$|Dead\s*Load)

Matches:

  • Dead Load
  • DL

Live Load Pattern

Regex pattern to identify live load parameters.

Default: (?:^LL$|Live\s*Load)

Matches:

  • Live Load
  • LL

Total Load Pattern

Regex pattern to identify total/point load parameters.

Default: (?:Point\s*Load|Total\s*Load)

Matches:

  • Point Load
  • Panel Point Load
  • Total Load

Load Resolution Logic

The tool requires either:

  1. A single Total Load parameter (Point Load, Panel Point Load, or Total Load), OR
  2. Both Dead Load and Live Load parameters (which are summed)

Elements with ambiguous combinations (e.g., both Total and Dead/Live values present) are skipped and reported.

Custom/Localized Names

Teams using localized parameter names (e.g., "Carga Muerta" for Dead Load) can configure the regex patterns to match their naming conventions. Simply update the appropriate pattern in settings to include your custom names.

Family Requirements

For the tool to calculate and update weights, your joist girder families must include specific parameters. The tool recognizes several common parameter names for flexibility.

Required Input Parameters

Parameter Purpose Accepted Parameter Names
Number of Joists Number of Joists, SpaceNum, Number of Equal Spaces
Point Load Identified via regex patterns configured in settings. Default patterns match Dead Load, DL, Live Load, LL, Point Load, Panel Point Load, and Total Load. The tool requires either a single Total/Point Load value or both Dead Load + Live Load (which are summed). Ambiguous combinations are skipped. Values are normalized to kips: numeric values are treated as kips, Force-typed parameters are converted to kips, and text values may include units like 10 kips, 10000 lb, or 45 kN.
Length Length (standard Revit parameter)
Depth Depth (standard Revit parameter)

Required Output Parameter

Parameter Requirements
Wt Must exist and be writable (not read-only or formula-driven)

Which Elements Are Processed?

The tool targets Structural Framing elements where family/type names match configured regex patterns.

Default family pattern:

^(?:(?:[BV]?G)|Vulcraft) Joist Girder$

This matches:

  • G Joist Girder
  • BG Joist Girder
  • VG Joist Girder
  • Vulcraft Joist Girder

Workflows

Workflow 1: Manual Weight Update

Use this workflow when you want to update all joist girder weights at a specific point in your design process.

  1. Complete your joist girder layout and verify parameters are filled in
  2. Navigate to the DB Tools ribbon tab
  3. Click Update Joist Girder Weights
  4. Review the completion message for any skipped elements and sample skip reasons
  5. Open a joist girder schedule to verify weight values

Workflow 2: Automatic Updates During Design

Use this workflow for active design development when parameters change frequently.

  1. Ensure auto-update is enabled in DB Tools settings
  2. Work on your model as usual—place joist girders, adjust parameters
  3. Switch between views periodically (floor plans, sections, 3D)
  4. Weight values update automatically each time you change views
  5. Check schedules anytime to see current calculated weights

Workflow 3: Preparing for Load Calculations

Use this workflow before exporting data for structural analysis.

  1. Complete all joist girder placement and sizing
  2. Verify all required parameters are populated on each element
  3. Run Update Joist Girder Weights manually
  4. Review the results for any warnings or skipped elements
  5. Fix any elements with missing parameters and run again
  6. Export your schedule or proceed with analysis

Tips & Best Practices

  • Use consistent family naming: Include "joist girder" in your family or type names so the tool recognizes them automatically

  • Populate parameters before running: The tool cannot calculate weights if input parameters (point load, number of joists, etc.) are missing or zero

  • Check the Wt parameter setup: Ensure the Wt parameter is not driven by a formula—it must be writable for the tool to update it

  • Run manually for large models: If you have hundreds of joist girders, consider disabling auto-update and running the tool manually to avoid slowdowns during view navigation

  • Verify results periodically: Spot-check calculated weights against manufacturer tables to ensure reasonable values

  • Create a QC schedule: Build a schedule showing joist girders with their input parameters and calculated weight to quickly identify incomplete elements

Troubleshooting

Weight not updating on specific elements

Possible Cause Solution
Family/type name doesn't match Family Name Pattern Update Family Name Pattern in settings to match your family names
Missing input parameters Add the required parameters to your family
Wt parameter is formula-driven Change the parameter to a simple value (remove formula)
Wt parameter is read-only Check if parameter is shared and locked; recreate if needed
Input parameter values are zero or blank Fill in the number of joists, point load, and verify length/depth

Tool seems slow or causes lag

Possible Cause Solution
Auto-update running on large model Disable auto-update; run manually when needed
Many joist girders being processed This is normal for large models; wait for completion

Calculated weights seem incorrect

Possible Cause Solution
Wrong units on input parameters Verify parameter units match expected values
Point load value is per-panel vs. total A populated Point/Panel Point/Total Load value wins over Dead/Live inputs. Clear or correct duplicate total-style parameters if the tool reports ambiguity
Depth parameter reading incorrectly Verify the family's depth parameter represents the actual joist girder depth

Tool is disabled or won't run

Possible Cause Solution
Warning system has disabled the tool Check for warning messages; resolve any blocking issues
No joist girder elements in model Place joist girder framing elements first

FAQ

Q: Does this tool work with all joist girder families?

A: The tool works with any Structural Framing family where the name contains "joist girder" and includes the required parameters. It's designed to be flexible with parameter naming to accommodate different family standards.

Q: How accurate are the calculated weights?

A: The weights are estimates based on moment-based calculations using your design parameters. They're suitable for preliminary design and load takeoffs but should be verified against manufacturer specifications for final design.

Q: Can I use this with nested joist girder families?

A: The tool reads parameters from the placed family instance. If your nested family exposes the required parameters at the instance level, it should work correctly.

Q: What happens if some joist girders are missing parameters?

A: Those elements are skipped during processing. Manual runs report Updated/Skipped counts and sample skipped reasons; auto-update skips silently when switching views.

Q: Does the tool modify anything besides the Wt parameter?

A: No. The tool only writes to the Wt parameter. All other parameters are read-only inputs to the calculation.

Q: Can I undo the weight updates?

A: Yes. Like other Revit modifications, the weight updates are part of Revit's undo history. Use Ctrl+Z or the Undo command to revert changes.

Q: Why would I disable auto-update?

A: Auto-update recalculates weights every time you switch views, which can cause brief pauses on large models. If you prefer snappier navigation, disable auto-update and run the tool manually when you need current values.

Q: My family has separate Dead Load and Live Load parameters. Does the tool handle that?

A: Yes. If both Dead Load and Live Load have values, the tool sums them to produce the total point load (e.g., 5 + 8 = 13). If only one is filled in, the element is skipped (unless a Total/Point Load value is provided instead).

Q: My family only has a single Panel Point Load parameter. Will it still work?

A: Yes. Panel Point Load is treated as a valid Total Load input.

Q: Does this work in workshared models?

A: Yes. The tool updates elements you have permission to edit. Elements owned by other users or checked out to others cannot be updated until you have edit access.

Q: My team uses localized or custom parameter names for Dead/Live loads (e.g., "Carga Muerta", "DL1"). How do I configure the tool?

A: Update the regex pattern settings to match your parameter names:

  1. Open DB Tools settings
  2. Find the Joist Girder Weight settings section
  3. Update the "Dead Load Pattern" field to match your dead load parameter names (e.g., (?:^DL1$|Carga\s*Muerta))
  4. Update the "Live Load Pattern" and "Total Load Pattern" fields similarly

The default patterns match common English names ("Dead Load", "DL", "Live Load", "LL", "Point Load", "Total Load"). Teams using other naming conventions should update these patterns to match their parameter names.

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