In brief
- To enable automatic clash detection in Model Coordination, turn on Convert Element Ids when exporting NWC from Revit.
- For Revit files, Navisworks uses shared coordinates by default.
- Faceting Factor defaults to 1; increasing it raises the model’s polygon count and the size of the Navisworks file.
- Model Coordination can combine NWC files, but automatic clash detection is available only for supported NWC types.
Choosing the right file format is only one part of exporting Revit models to Navisworks or Autodesk Model Coordination. Autodesk’s Navisworks 2023 Revit file reader documentation describes options for element IDs, coordinates, linked files, properties, and geometry detail. Model Coordination documentation also identifies enabling element IDs when exporting NWC from Revit as a required step for automatic clash detection. The steps below explain these two workflows separately.
1. First, determine how the NWC file will be used
NWC is one of the formats supported for model aggregation in Model Coordination. However, not every NWC file supports automatic clash detection: Autodesk’s documentation says that NWC files exported from Revit and tracked support this feature, while other NWC files do not. These files can still be viewed and combined with models, and used in other workflows such as Save to Files or object coloring. So if the deliverable is intended for automatic clash detection, prepare the file accordingly.
Clarify the target workflow. Will you run automatic clash detection in Model Coordination, or simply view the model alongside models from other disciplines? The functions supported by the file type depend on this choice.
Enable Convert Element Ids when exporting NWC. Autodesk recommends turning on this option when creating NWC files from Revit for Model Coordination. This helps Model Coordination recognize that the file came from Revit and include it in automatic clash detection.
Verify the file’s functionality after uploading. The fact that an NWC appears in model aggregation does not, by itself, mean it supports automatic clash detection. Treat these as separate capabilities.
2. Check coordinates and model scope
In the Navisworks 2023 Revit file reader, the coordinate setting is important for consistently evaluating the position of different models. The default is Shared; this uses the shared coordinates defined in the Revit file. Project Internal loads the model at the 0,0,0 origin in the Revit Project North orientation. Choosing Shared does not guarantee that models will align: if shared coordinates from the main Revit model have not been published to linked models, they may appear misaligned in Navisworks.
| Setting | Recommended value | Effect |
|---|---|---|
| Convert Element Ids | On for automatic clash detection in Model Coordination | Helps identify the NWC’s Revit source and include it in the clash detection workflow. |
| Coordinates | As agreed by the team; defaults to Shared | Uses the shared coordinates defined in the Revit file. Models may appear misaligned if coordinates have not been published to linked models. |
| Convert | Navisworks view, First 3D view, or Entire project, as needed | Determines which visible elements or project scope will be loaded. |
| Faceting Factor | 1 (default) | Controls the level of detail used to facet surfaces into polygons. |
Agree on the coordinate system with the project team. When using Shared, models may appear misaligned if shared coordinates have not been published to linked models. Autodesk recommends that model authors agree on a coordinate system before creating and sharing models.
Choose which view to load. Navisworks view is the default option; when a 3D view in Revit includes “Navis” in its name, that view is loaded. If this condition is not met, Revit’s first 3D view is loaded. The other options load the first 3D view or the entire project.
Set Faceting Factor as needed. The value must be 0 or higher; 0 turns off faceting. The default is 1. Doubling the value doubles the polygon count; halving it also halves the polygon count. Higher values produce more polygons and larger Navisworks files.
3. Configure properties, links, and geometry for the task
For converting Revit parameters, None means that parameters are not converted. Elements converts the parameters of elements found in the model; All converts the parameters of elements along with those of referenced elements. Selecting All makes additional property tabs available in Navisworks. Rather than assuming all this data is needed for every handoff, choose settings based on review and coordination requirements.
Decide whether to retain element properties. When Convert Element Properties is enabled, Revit element properties are converted to Navisworks properties. If the option is turned off, the original Revit properties are retained. Element IDs and element properties are separate options; enabling one does not automatically determine the other.
Review linked files. Convert Linked Revit Files is off by default; when enabled, linked RVT files are included in the NWC. Convert Linked CAD Formats is also off by default and can include linked CAD files such as DXF, DGN, SAT, and SketchUp. According to Autodesk documentation, linked DWG files and some other formats are not included under the option to export linked RVT files.
Check room geometry and project structure options. The documentation associated with Revit 2022 says that room geometry is converted into subparts by default; turning this option off preserves the original room object. Divide File into Levels is on by default and organizes Revit files at the File, Category, Family, Type, and Instance levels. These options can affect how the model is reviewed in Navisworks.
What this means for architecture, interior design, and archviz teams
Architects and interior designers should pay particular attention to the Shared and Project Internal settings when combining discipline models. Shared uses the shared coordinates defined in the Revit file; coordinates that have not been published to linked models can cause misalignment. For BIM coordination teams, Convert Element Ids is critical to enabling automatic clash detection; even when a model is intended only for visual comparison, the capabilities supported by the file type should still be checked. Archviz teams should also bear in mind that increasing geometry detail increases file size. The documentation specifies no hardware requirements or licensing costs, so offices should test export settings and performance with their own project files.
Common mistakes
Attributing model misalignment only to the export: Shared coordinates in the main Revit model may not have been published to linked models.
Skipping Convert Element Ids: Even if an NWC appears in Model Coordination, it may not be suitable for automatic clash detection.
Increasing Faceting Factor unnecessarily: A higher value means more polygons and a larger file.
Assuming linked files are included automatically: The relevant options for Revit and CAD links are off by default.
Sources
2 sourcesSource texts are not republished; short quotes are marked, everything else is our own summary and commentary.
For architecture and BIM offices in Turkey, standardizing these settings from the outset can help reduce recurring issues, particularly models opening misaligned or being excluded from clash detection. The most important practical steps are to agree on a coordinate system as a team before handing off NWC files and to check the element IDs.
Increasing the Faceting value does not always mean a better result: detail increases, but so does file size. Offices should therefore test the required geometry and property scope using their own project files. The documentation does not specify hardware requirements or licensing costs, so no assumptions should be made about these items.
Frequently asked questions
How do I enable automatic clash detection for a Revit NWC file in Model Coordination?
Enable Convert Element Ids when exporting NWC from Revit. Autodesk says this helps Model Coordination recognize the file as originating from Revit and include it in automatic clash detection.
Which coordinate option does Navisworks use for Revit models?
The default option in the Navisworks Revit file reader is Shared. It uses the shared coordinates defined in the Revit file; misalignment may occur if coordinates have not been published to linked models. Project Internal loads the model at the 0,0,0 origin in the Revit Project North orientation.
What changes when Faceting Factor is increased?
As the value increases, the model’s polygon count rises and the Navisworks file gets larger. The default value is 1; 0 turns off faceting.
