Introduction: Why Arrays Matter in Revit
If you've ever found yourself manually copying dozens or hundreds of identical elements in Revit, you know the pain of repetitive modeling. Whether you're placing chairs in an auditorium, lights in a grid pattern, or shelves in a storage unit, Arrays are your solution to smart, parametric repetition.
Arrays in Revit allow you to create infinite copies that all behave as one unit. The genius? You only need to control two elements to control everything else. But here's the crucial rule that many beginners miss: the item you array cannot be modeled in-place or built directly within the current family. It must be a single, self-contained object—like a finished, loadable family or nested family.
In this comprehensive guide, we'll cover everything you need to know about Revit Arrays, including the revolutionary 2025 update that solves the long-standing "Array of 1" problem.
What are Arrays and why use them?
Understanding Arrays at the project Level
At its core, an Array is a tool that creates parametric copies of an element in a specific pattern. Think of it as a fancy copy tool where the copies remain grouped, meaning you can easily change the number of items or their spacing later.
Setting up a basic linear array in a project:
- Load your family: Go to Insert tab → Load Family
- Place your element: Use Architecture tab → Component to place a single instance
- Create the array: Select your element, go to Modify tab → Array (or type AR)
- Configure settings:
- Ensure "Group and Associate" is checked in the Options Bar
- Select "Linear" for straight-line repetition
- Choose "Second" method for precise spacing control
- Define the pattern: Click your starting point, then click to set the distance between first and second items
- Adjust count: Change the number in the Options Bar to set total copies
Creating radial arrays
For circular arrangements like chairs around a table or lights in a circular pattern:
- Select your element and start the Array command
- Choose "Radial" in the Options Bar
- Set center of rotation: Click "Place" and define your center point
- Define the pattern:
- "Second" method: Sets angle between each item
- "Last" method: Sets total sweep angle and distributes items evenly
The "Last" method is particularly useful when you need to fit a specific number of items within a defined arc, like fitting 8 chairs around three-quarters of a circular counter.
Family Editor: Where arrays become powerful
The Golden Rule: Always use nested families
Critical Best Practice: Inside the Family Editor, ALWAYS create arrays using nested families, never raw geometry.
Here's why this matters:
- Raw geometry arrays break: When you array extrusions or sweeps created directly in your host family, they create visible seam lines and don't join properly
- Nested families stay clean: Arraying a nested family encapsulates the geometry and behavior, making your array robust and predictable
- Better performance: Nested family arrays are more stable and efficient in your overall model
Setting up for success
Before creating arrays in the Family Editor:
- Align your first element: Use the Align tool (AL) to position your nested family relative to reference planes
- Lock the alignment: This creates a stable framework for your parametric array
- Focus on precision: Only the first element needs precise alignment—the array will follow
Linear arrays: "Second" vs "Last" methods
The "Second" method (recommended)
When to use: When you need precise control over spacing between items
How it works: You define the exact distance between the first and second items, and Revit repeats that spacing throughout the array.
Best for: Consistent modular spacing like shelves, locker compartments, or structural elements where spacing is critical.
The "Last" method
When to use: When you know your total length constraint but want to vary the number of items within it
How it works: You define the total span from first to last item, and Revit distributes items evenly within that distance.
Best for: Cabinets of fixed width that need variable numbers of drawers, or fitting elements within specific boundaries.
Connecting arrays to parameters
This is where arrays become truly powerful for parametric design:
- Select your array group
- Access Properties: In the Properties Palette, find the "Number" parameter
- Create parameter: Click the "Associate Family Parameter" icon → "New Parameter"
- Configure parameter:
- Name: "Number of Shelves" (or relevant name)
- Type: Integer
- Group: Construction or Dimensions
- Instance vs Type: Instance for more flexibility
- Test in Family Types: Use the Family Types dialog to change values and watch your array update automatically
Pro tip: These parameters can be driven by formulas, allowing for complex parametric relationships based on overall family dimensions.
The Big Decision: When Are Arrays Worth It?
Arrays add complexity
Arrays create grouped elements that require entering a group editor to modify individual components. This can become cumbersome with many arrays or nested arrays.
When arrays are worth it:
- Variable repetition: The number of items changes frequently
- Homogeneous elements: All items are identical and move together
- Large quantities: Arrays with 5+ items show clear benefits
- Parametric control: You need the count driven by parameters or formulas
When to avoid arrays:
- Small counts: For 3 or fewer items, individual copies are simpler
- Individual variations needed: Each item requires different properties
- Static situations: Number rarely changes
- Performance concerns: Very large arrays (100+ items) can impact model speed
Array limitations you must know
1. No individual differences
The problem: You cannot easily have individual variations within an array group. Changing one element affects all elements in the array.
Impact: If you need some chairs with arms and others without, or some shelves glass and others wood, arrays won't work. You'd need to ungroup them, losing parametric benefits.
2. Performance considerations
Large arrays can impact model performance, especially:
- Arrays with hundreds or thousands of instances
- Complex nested families within arrays
- Multiple arrays within a single family
- Projects with many arrayed families
Game changer: Revit 2025 update
The "array of 1" problem (pre-2025)
Before Revit 2025, setting an array count to "1" would:
- Break the array entirely
- Delete elements
- Generate errors
- Force complex workarounds using Yes/No visibility parameters
The 2025 solution
Revolutionary change: Revit 2025 finally allows arrays with a count of "1"!
What this means:
- Arrays maintain integrity with single instances
- No more complex visibility workarounds
- Seamless flexibility from 1 to unlimited items
- Simplified family creation workflow
Why it matters: This simple change makes arrays exponentially more useful for dynamic families and eliminates major pain points for content creators.
Advanced tips for students and new professionals
1. Start simple
- Practice with basic rectangular arrays before attempting complex radial patterns
- Master the "Second" method before exploring "Last" method applications
2. Plan your reference framework
- Always establish clear reference planes before arraying
- Use consistent naming conventions for your reference planes
- Lock critical alignments to prevent accidental movement
3. Test parametric behavior
- Always test your arrays at extreme values (1 item, maximum items)
- Check array behavior when family is flexed to different sizes
- Verify performance with realistic item counts for your use case
4. Document best practices
- Name your array parameters descriptively ("Shelf Count" not "Number")
- Group related parameters logically in the Properties palette
- Include parameter tooltips when creating custom families
5. Quality assurance workflow
- Test arrays in both family editor and project environment
- Verify array behavior when family types change
- Check model performance with realistic array sizes
When to consider alternatives
Manual copying
Best for:
- 2-3 identical items
- Items that need individual modification
- One-time arrangements
Specialized BIM content
Consider: High-quality manufacturer families that provide configurability without array complexity. These often offer:
- Built-in parametric control
- Optimized performance
- Manufacturer data integration
- Professional quality assurance
Conclusion: Mastering arrays for better BIM
Arrays are powerful tools for identical repetition in Revit, offering parametric control that can significantly speed up your modeling workflow. Remember these key takeaways:
Essential rules:
- Always use nested families, never raw geometry
- Only array when repetition truly benefits from parametric control
- Consider maintenance complexity vs. benefits
2025 Game changer:
- The "array of 1" capability revolutionizes family creation
- Eliminates major workflow bottlenecks for content creators
Best practices:
- Master both "Second" and "Last" methods
- Connect arrays to parameters for maximum flexibility
- Always test at extreme values
- Consider performance implications for large arrays
For Students: Start with simple arrays and gradually build complexity as you master the fundamentals. Understanding when NOT to use arrays is as important as knowing how to create them.
For New Professionals: Focus on creating robust, maintainable families that your team can easily understand and modify. Well-planned arrays can be powerful assets, but poorly implemented ones become maintenance nightmares.
Arrays represent just one tool in your parametric modeling toolkit. Master them, but always choose the right tool for each specific situation. Your future self (and your teammates) will thank you for the thoughtful approach.