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Linking Revit models and interference checking between disciplines

Linking Revit models in 2027: seven positioning options, overlay against attachment, the redesigned Manage Links dialog, and interference checks.

  • Dr. Nguyen Manh Tuan
  • 12 min read
A link keeps a path to the other file, while an import swallows the content into yours Photo: Diagram by the Institute of Information Technology in Civil Engineering

Linking Revit models brings someone else's model into your project without pulling it into your file. Their model stays in their file; yours holds only a path and a position.

Because of that, whatever they change appears as soon as you reload, and your file does not grow. To learn modelling and documentation end to end, see the Revit Architecture course.

OptionWhat it does
LinkReferences an external file. Their edits show in your project. This is the correct way to collaborate
ImportPulls the content into your file. The file grows, and it can never be updated again

Import suits only content that will never change. The same choice applies to CAD backgrounds, covered in linking CAD into Revit.

The tool sits on the Insert tab, Link panel, button Link Revit.

The Import/Link RVT dialog Photo: The Positioning row at the foot of the Import/Link RVT dialog
No.ComponentWhat it means
1PositioningA row of its own at the foot of the dialog, deciding where the other model lands. It is the most important setting, and the one most often chosen wrongly
The seven positioning options Photo: The Positioning list with its seven entries
PositioningWhen to use it
Auto - Center to CenterOverlays the centres of the two models. Quick, and almost always wrong, because the centre shifts with whatever the model contains
Auto - Internal Origin to Internal OriginOverlays the internal origins. The default, and correct when both sides modelled from one agreed origin
Auto - By Shared CoordinatesUses declared shared coordinates. The right choice on a large site with several buildings
Auto - Project Base Point to Project Base PointOverlays the two project base points
Manual — Internal Origin, Base Point, CenterThree manual options: you click the insertion point yourself

Agreeing the origin is work to be done before anyone starts modelling, not once models exist. For housing the tidiest rule is that every discipline takes the intersection of grid A and grid 1 as the origin.

The error when linking an open file Photo: Revit refuses to load a file that is already open in the same session

One trap worth knowing: a file already open in the same Revit session cannot be linked. Close it and link again; if it has to stay open, make a copy and link the copy.

A linked model sitting out of alignment Photo: Three signs that two models do not share an internal origin
No.ComponentWhat it means
1The newly linked modelThe two files have different internal origins, so the other plan lands askew and lines run outside the site
2The host project's planYour own work: the grid, room names and dimensions
3The grey area behindThe linked view's crop region is larger than the host's. This is the easiest sign to spot when origins disagree

Linking is not only for joining architecture to structure. On a masterplan or a terrace of houses, the neighbouring building is often linked in to see how far it shades the site and blocks the view.

Link a model that itself links several other files, and Revit raises a dialog straight away.

The Nested Links Invisible dialog Photo: The files the incoming model links, with the reason they do not appear
No.ComponentWhat it means
1The nested link listThe nine files that model itself links, among them site, structure, interiors, electrical, HVAC and plumbing
2Why they are hiddenTheir Reference Type is Overlay. An overlaid link appears only in the file that holds it
3The fixOpen Manage Links in that file and switch the Reference Type to Attachment. Changing it in the host has no effect
The two reference types Photo: The Reference Type field with Overlay and Attachment
Overlay against attachment Photo: A chain of three files and what the third person sees in each case

Overlay does not pass through: a third person linking your model will not see the model you borrowed. It is the default and the safe choice. Attachment passes the whole chain along, which easily leads to heavy, duplicated files. Autodesk explains the mechanism on About Nesting Linked Models.

The nested-links dialog appears once, and carries a Do not show me this message again box. Plenty of people dismiss it, then cannot work out why several disciplines are missing from the model.

Manage Links on the Insert tab opens the control panel for every link in the project. The 2027 release redesigned it completely.

The Manage Links dialog Photo: One loaded Revit link and one image whose path has broken
No.ComponentWhat it means
1The Revit linkA green tick under Status means Revit found the file and finished loading it
2Path Type RelativeA relative path: copy the whole folder to another machine and the link still resolves. Absolute breaks on any move
3An image with a broken pathA yellow triangle, with an absolute path pointing at the modeller's own drive. This is exactly the dangling reference to watch for

Older releases split this dialog into tabs for Revit, IFC, CAD Formats, DWF Markups, Point Clouds and Topography. The 2027 release merges them into one table with filter and search boxes, so older tutorials describing those tabs will not match. Autodesk documents the new dialog on Use the Manage Links Dialog.

The practical rule on paths: keep every file of one project inside a single folder tree, use relative paths, and when sending the set out, zip the whole tree rather than posting files individually.

Unload, remove or reload, and halftoning another discipline

CommandWhat it does
UnloadUnloads the model. It vanishes from screen but the path remains, ready to reload at any time
RemoveDeletes the link from the project. Getting it back means linking again from scratch
ReloadReloads from the source file. Use it when the other team reports an update

Revit warns plainly on removal: it cannot be undone with Undo. So when another discipline is simply in the way for now, use Unload rather than Remove.

Linked models have their own tab in Visibility/Graphics, called Revit Links. There you choose By Host View to draw by the current view's settings, By Linked View to follow a view inside the linked file, or Custom to set it yourself.

The familiar move is to set another discipline to Custom and turn on Halftone: the architectural drawing stays legible while the structure remains visible behind it. That dialog is covered in hiding and showing elements in Revit.

Copy/Monitor: watching the other team's grids and levels

A link lets you see the other model. Grids and levels deserve more than seeing: two disciplines have to share one setting-out system, and when one side moves a grid the other must be told.

The Coordinate panel Photo: The seven buttons of the Coordinate panel on the Collaborate tab
ButtonWhat it does
Copy/MonitorCopies grids, levels, columns, walls and floors from a linked model and monitors them
Coordination ReviewLists the changes the other team has made to monitored elements
Reconcile HostingFinds components orphaned because the other side deleted a wall or floor
Interference CheckClash detection, covered below

The Copy/Monitor Options dialog has exactly five tabs: Levels, Grids, Columns, Walls and Floors. Those are the only categories that can be copied and monitored. Within them, Reuse Levels with the same name is on by default and should stay on, because clearing it makes Revit create a duplicate level on top of the existing one every time.

When the other side edits, Coordination Review offers four responses: Postpone, Reject, Accept difference, and Modify to follow their change.

Avoid Copy/Monitor on walls and floors unless it is genuinely needed: there are many of them, and every change on the other side raises another item to clear. For housing, monitoring levels and grids is enough. Drawing and editing grids is covered in grids and levels in Revit.

Interference Check: clash detection inside Revit

Two disciplines modelling in the same volume will always overlap somewhere. Finding those places on paper is very hard; Revit does it with one command.

The Interference Check dialog Photo: Two category columns and the three quick-selection buttons
No.ComponentWhat it means
1Categories from, leftThe first source: Current Project or a linked model
2Categories from, rightThe second source. Different sources check between two models; the same source checks within one
3SelectionAll, None and Invert tick a whole column quickly

Do not tick every category on both sides. The result runs to thousands of rows, most of them ordinary overlaps such as a wall meeting a floor. Run one pair of categories at a time and the list stays readable.

The Interference Report Photo: The clash list with the Show, Export, Refresh and Close buttons
No.ComponentWhat it means
1Group byHow the list is grouped, by the two categories by default
2The clash listExpand a branch to see each pair of overlapping elements
3Four buttonsShow jumps to the selected clash; Export saves the report; Refresh re-runs after a fix; Close exits

Refresh is the one to remember: fix a clash, click Refresh, and that row disappears from the list without re-running the whole command.

Export writes a report that opens in a browser, each row naming the category, family, type and id of both elements. The number after id is exactly what goes into Select by ID on the Manage tab, Inquiry panel: Revit jumps straight to that element. It is the quickest way to work through a clash report with someone at a distance.

The tool has limits. It finds geometric clashes within the Revit file and its linked models only, with no tolerance settings and no rule sets. Once a project federates many disciplines and clashes need managing in rounds, a dedicated tool takes over, as covered in what Navisworks is used for. Autodesk documents the command on Interference Checking.

A thirty-minute exercise. It runs through linking Revit models end to end; you need two Revit files of the same building.

  1. Open the host file. Go to Insert, Link panel, Link Revit.
  2. Choose the second file, set Positioning to Auto - Internal Origin to Internal Origin, then Open.
  3. If Revit refuses to load it, check whether that file is open in the same session.
  4. Look at the plan: do the two models align, or not. Note the sign that told you.
  5. Open Manage Links and read the Status and Path Type columns. Switch Path Type to Relative if it is Absolute.
  6. Click Unload, then Reload, watching the screen after each.
  7. Type VG, open the Revit Links tab, set the link to Custom and turn on Halftone.
  8. Go to Collaborate, Coordinate panel, and run Interference Check between the Walls of both models.
  9. Click Show on one row to jump to the clash, then Export the report to a file.
  10. Open the report, copy an id number, and use Select by ID on the Manage tab to jump to that element.

Step 6 shows plainly how unloading differs from removing; step 10 is the biggest time-saver in the whole article.

Frequently asked questions

What is the difference between link and import?

A link keeps a path to the other file, so it can be updated. An import pulls the content into your own file, which grows it and rules out any later update.

Why does the linked model sit askew over my plan?

The two files have different internal origins and it was linked with Center to Center. Relink with Internal Origin to Internal Origin, or use shared coordinates on a multi-building site.

I linked a model but several disciplines are missing. Why?

The nested links inside it have their Reference Type set to Overlay. Open Manage Links in that file and switch them to Attachment.

Can Revit's Interference Check replace Navisworks?

Not entirely. It finds geometric clashes within the Revit file and its links, with no tolerance settings and no rule-based rounds.

About the author

Dr. Nguyen Manh Tuan — BIM lecturer at the Institute of Information Technology in Civil Engineering – Hanoi University of Civil Engineering