How to export nwc from revit

What is an NWC File?

An NWC file is a Navisworks Cache file. It's essentially a temporary file that Navisworks creates when it opens or links to other file formats, including those from Revit. These files contain geometric data and other information that allows Navisworks to display and interact with the model efficiently. While NWC files are primarily for internal use by Navisworks, they can sometimes be useful for specific workflows, although exporting to the NWD format is generally more common for sharing and archiving.

Why Export from Revit to Navisworks Formats?

Autodesk Revit is a powerful Building Information Modeling (BIM) software used for architectural design, structural engineering, and MEP (mechanical, electrical, and plumbing) engineering. Navisworks is a project review software that allows users to aggregate and combine models from various disciplines and file formats into a single, cohesive model. Exporting from Revit to Navisworks formats (NWC, NWD, or NWF) is crucial for:

• Clash Detection: Identifying potential conflicts between different building systems (e.g., structural beams clashing with ductwork).
• Model Aggregation: Combining models from various disciplines (architectural, structural, MEP) into one federated model.
• 4D Simulation (Time-Liner): Visualizing the project schedule and construction sequence.
• Model Review and Quantification: Performing detailed reviews, taking measurements, and extracting quantities.
• Coordination: Facilitating communication and coordination among project stakeholders.

How to Export NWC (or NWD/NWF) from Revit

The primary method for exporting Revit models to Navisworks formats involves using the Navisworks Exporter plugin. This plugin is typically installed automatically when you install Navisworks Manage or Navisworks Simulate. If you have Navisworks installed, the exporter should be integrated into your Revit interface.

Using the Navisworks Exporter Plugin in Revit:

1. Open your Revit Project: Ensure the Revit project file (.RVT) you wish to export is open in Revit.
2. Locate the Add-Ins Tab: In the Revit ribbon, navigate to the 'Add-Ins' tab. You should see a section dedicated to Navisworks.
3. Initiate the Export: Within the Navisworks section, you'll find options like 'Export NWC', 'Export NWF', or 'Export NWD'. For NWC, select 'Export NWC'.
4. Configure Export Settings (Optional but Recommended): Before exporting, it's often beneficial to configure the export settings. Click on the 'Export NWC' button (or the gear icon next to it, depending on the version) to open the Navisworks Exporter settings dialog.
   • Units: Ensure the units match your project or the intended use in Navisworks.
   • Properties: Decide which element properties you want to export. Including relevant properties is crucial for quantification and clash detection. You can choose to export element properties, shared parameters, or custom sets.
   • Files of Record: This setting is more relevant when exporting NWF or NWD, allowing you to specify which files are considered the 'official' versions.
   • Batch Export: For exporting multiple Revit files or creating NWD/NWF files, you might use the batch export options.
5. Perform the Export: Once settings are configured (or if you're using defaults), click 'Export' or 'OK'. Revit will process the model and generate the NWC file. You will be prompted to save the file in a location of your choice.

Alternative: Exporting to NWD or NWF

While you asked about NWC, it's important to understand that NWD and NWF are often more practical for project coordination and review.

• NWF (Navisworks File): This file type acts as a link or container. It points to the original Revit files (and other source files) and doesn't embed them. When you open an NWF in Navisworks, Navisworks will attempt to find and load the linked original files. This is useful if the source files are frequently updated, but it requires all users to have access to the original files.
• NWD (Navisworks Document File): This is a published, self-contained file format. It embeds the entire model geometry, properties, and any review data (redlines, comments) into a single file. NWD files are ideal for sharing with external stakeholders who may not have access to the original design software or files. They are also good for archiving project data. You can export directly to NWD from Revit using the plugin.

To export to NWD or NWF, follow the same steps as for NWC, but select the appropriate option from the Navisworks Exporter menu in Revit's Add-Ins tab.

Troubleshooting and Best Practices

• Version Compatibility: Always ensure that your version of the Navisworks Exporter plugin is compatible with both your Revit version and the version of Navisworks you intend to use. Outdated or incompatible exporters can lead to errors or incomplete exports.
• File Size: Revit models can be large. Exporting with all properties can significantly increase file size. Consider what information is truly necessary for the review process in Navisworks. You might need to experiment with different property sets.
• Performance: If you experience slow export times or performance issues in Navisworks, try exporting only necessary elements or simplifying the Revit model before export. Sometimes, exporting to NWD or NWF can offer better performance than relying solely on NWC files linked from Revit.
• Linked Revit Models: If your main Revit project contains linked Revit files, the exporter should handle these automatically. Ensure all linked files are correctly loaded in your Revit session before exporting.
• Revit Add-In Not Appearing: If the Navisworks Exporter add-in doesn't appear in Revit, try reinstalling Navisworks, as this usually installs the exporter. You can also check the Add-In Manager within Revit to ensure it's enabled.

By understanding the different Navisworks file formats and utilizing the exporter plugin correctly, you can efficiently transfer your Revit project data for comprehensive review and coordination in Navisworks.