How To Duplicate An Assembly In Revit?

The core method for duplicating an assembly in Revit is to copy and paste the assembly's elements, then slightly modify the new version to force Revit to create a new, unique assembly type.

Because Revit automatically recognizes identical assemblies as the same type, you must break the association with the original type to create an independent, editable duplicate.

Method: Copy, paste, and force a new type

This method is the most reliable for creating an assembly that is independent of the original, allowing you to modify it without affecting other instances of the original type.

1. Select the Assembly: In a plan or 3D view, hover over and select the assembly you wish to duplicate. You may need to use the Tab key to select the entire assembly rather than just a single element within it.
2. Copy the Elements: Use the standard Copy to Clipboard command by pressing Ctrl + C or by clicking the icon on the Modify tab.
3. Paste the Elements: Immediately paste the elements into the same location by using Paste > Aligned to Same Place.
4. Disrupt the Association: With the newly pasted assembly still selected, you must change it slightly so Revit registers it as a new, unique assembly. A simple way to do this is to remove a single component from the assembly.
   • Click Edit Assembly on the Modify | Assemblies tab.
   • Click the Remove button in the Edit Assembly toolbar.
   • Select one of the assembly's components and click Finish.
5. Create the New Assembly: After removing the component, Revit automatically creates a new assembly type because the new instance is no longer identical to the original.
6. Re-model the Removed Element: To restore the assembly to its intended form, re-enter the Edit Assembly mode and model the component you just removed. Because its element ID is now different, Revit will not merge it back into the original assembly type.
7. Create New Views (if needed): If you require specific views or sheets for the new assembly type, select it and use the Create Views command on the Modify | Assemblies tab.

Understanding Revit's assembly logic

To effectively manage your assemblies, it's crucial to understand how Revit differentiates between and groups them.

The criteria for matching assemblies

• Identical Naming Category: The Naming Category must be the same for two assemblies to be considered a match. If you change this category, you can force Revit to create a new assembly type, even if the elements are identical.
• Identical Elements: Assemblies must contain the same number of elements from the same categories and types. Any difference in element count or type will force a new assembly to be created.
• Identical Geometric Properties: Elements in corresponding positions must have identical geometric properties. For example, if a window is in the same wall and at the same position, the assemblies will be a match. Any change in position or dimension will break the match.

Why simple duplication doesn't work

If you simply copy and paste an assembly without making any changes, Revit will recognize the new instance as belonging to the same assembly type. This means:

• Any edits to the original assembly's type will apply to all instances, including the "duplicate".
• Revit does not create a new assembly type in the Project Browser.

What happens during modification

When you edit an instance of an existing assembly type, Revit checks if the new configuration is unique.

• If it's unique: Revit automatically creates a new assembly type and issues a warning: "Edits caused a new assembly type to be created".
• If it matches an existing type: The instance is simply assigned to that matching assembly type.

Managing assemblies with groups

For some workflows, especially with highly repetitive elements like repetitive apartments, using groups can be a more efficient alternative to assemblies.

The workflow

1. Create a group of the elements you want to use repeatedly (e.g., a bathroom layout).
2. Create an assembly from one instance of that group for documentation purposes.
3. Place multiple instances of the group in your project.
4. If you need to make changes, you can edit the group, and the changes will be replicated across all instances of that group.

The limitations of this method

• Editing the assembly after grouping can be challenging.
• Assembly views may not update correctly after editing a group.
• Moving elements within the assembly views can be restricted.

Alternative methods and considerations

Using add-ins

For projects with many complex assemblies, add-ins like EzAssembly from the Autodesk App Store can automate the duplication process and handle associated views and sheets. This can save a significant amount of time and reduce the risk of manual errors.

Copying assemblies between projects

If you need to duplicate an assembly into a different project, use the Copy to Clipboard and Paste Aligned to Selected Views methods.

• Open both projects in the same Revit session.
• Select the assembly in the source project and copy it.
• Paste it into the target project.
• Note: If the assembly has associated views and sheets, these must be copied separately, or you can use a third-party tool.

Duplicating assembly views and sheets

Once a unique assembly type exists, you can create its documentation views.

1. Find the assembly type in the Project Browser, right-click, and select Create Assembly Views.
2. Duplicate assembly views by right-clicking on them in the Project Browser and choosing Duplicate or Duplicate with Detailing. Remember that simple duplication creates independent views.

Summary of workflows