Load Cases

Load cases are named groups that organize your structural loads into logical categories. Each load in your model belongs to exactly one load case, allowing you to analyze different loading scenarios separately and combine them later.

What are Load Cases?

In structural engineering, loads are typically grouped by their nature and source. Common load case types include:

  • Dead Load (D or G) — Permanent loads from the structure's own weight, fixed equipment, and finishes
  • Live Load (L or Q) — Variable loads from occupancy, furniture, and movable equipment
  • Wind Load (W) — Loads from wind pressure on the structure
  • Snow Load (S) — Loads from snow accumulation on roofs
  • Seismic (E) — Earthquake-induced loads
  • Roof Live (Lr) — Maintenance and temporary loads on roofs

This organization allows you to apply different load factors and create load combinations as required by design codes.

Opening the Load Cases Dialog

Access the Load Cases dialog by clicking the Load Cases button in the ribbon toolbar. This opens a spreadsheet-style interface where you can manage all your load cases.

Managing Load Cases

The Load Cases dialog presents a table with the following columns:

  • ID — A unique identifier for referencing the load case (e.g., "1", "2", "DL")
  • Title — A descriptive name (e.g., "Dead Load", "Live Load")
  • Notes — Optional notes or descriptions for documentation
  • Color — The display color for loads in this case (click to customize)

Adding Load Cases

Simply type in an empty row to create a new load case. At minimum, provide an ID to make the load case valid.

Editing Load Cases

Click any cell to edit its value. Changes are tracked but not applied until you click Apply or Apply and Close.

Deleting Load Cases

Clear the ID field to mark a row for deletion. When you apply changes, empty rows are removed. Note: Deleting a load case will also delete all loads assigned to that case.

Dialog Actions

The dialog toolbar provides several actions:

  • Download CSV — Export load cases to a spreadsheet file
  • Copy — Copy table data to clipboard
  • Save as Preset — Save your load case setup for reuse in other projects
  • Reload — Discard changes and reload from model or from saved presets

Load Case Colors

Each load case has an assigned color that determines how loads are displayed on the model:

  • Click the color swatch in the table to open the color picker
  • Choose from the preset palette or select a custom color
  • Loads are displayed in their load case's color, making it easy to identify which loads belong to which case
  • Default colors are automatically assigned from a predefined palette

Active Load Case

When viewing your model, you can select which load case to display. The active load case affects:

  • Which loads are visible on the canvas
  • Which load case new loads are assigned to when created via context menu

Use the load case selector dropdown in the ribbon to change the active load case.

Self-Weight

Self-weight is a special automatic load calculated from member sections and materials. It is controlled per load case — see the Self Weight documentation for details.

Analysis with Load Cases

When you run analysis:

  1. Each load case is analyzed independently
  2. Results are stored separately for each load case
  3. You can view results for individual load cases
  4. Load combinations can then combine results from multiple cases using factors

Best Practices

  • Use clear, descriptive names that indicate the load type (e.g., "Dead Load" rather than "LC1")
  • Keep load case IDs short for easy reference in load combinations
  • Use consistent naming conventions across projects
  • Document assumptions in the Notes field
  • Create separate load cases for loads that may need different factors in combinations