Importing geometry into Revit can be achieved primarily by importing DWG files, or through other formats and methods depending on the source and desired outcome. Here's a breakdown of the most common approach:
Importing DWG Files Directly
This is the most straightforward method if you have the geometry in a DWG format.
- Open Revit: Start a new project or open an existing one.
- Choose the Import Method: Go to the "Insert" tab on the Revit ribbon. You'll find a few options:
- Import CAD: This directly imports the DWG file, linking it to your Revit project. Changes made to the original DWG file will update in your Revit project when you reload it.
- Link CAD: This creates a link to the DWG file, meaning changes in the DWG will be reflected in Revit upon reloading. This is generally preferred for collaborative workflows.
- Select the DWG File: Browse to the location of your DWG file and select it.
- Import Settings: In the Import CAD Formats dialog, configure the import settings carefully:
- Colors: Choose how colors are handled (e.g., Invert, Preserve, Black and White).
- Layers/Levels: Specify which layers to import. You can import all layers or select specific ones.
- Import Units: Revit attempts to detect the units used in the DWG file. Verify these are correct (e.g., feet, meters, inches). Incorrect units will result in incorrectly scaled geometry.
- Positioning: Select how the DWG will be positioned within the Revit project. "Auto - Origin to Origin" is a common choice, placing the DWG's origin at the Revit project's origin. "Auto - Center to Center" is also a possibility. Consider "Manual - Center" or "Manual - Origin" if you need precise placement using your mouse.
- Place At: Choose the Revit level to associate the imported geometry with.
- Click Open: The DWG geometry will be imported into your Revit project.
Working with Imported Geometry
- Explode (Partial or Full): After importing, you may want to explode the DWG geometry to convert it into Revit elements. Be aware that exploding complex DWGs can create a large number of individual elements, which can impact performance. Consider using a "Partial Explode" first.
- Trace Over: Often, the best approach is to use the imported DWG as a reference to trace over and recreate the geometry using native Revit elements (walls, floors, roofs, etc.). This creates a more intelligent and manageable Revit model.
- Create In-Place Family: Create an In-Place Family (Architecture > Component > Model In-Place > Choose a category like "Generic Model") and import the DWG into the family. This can keep your main Revit model more organized, especially if the imported geometry represents a complex or unique object.
Alternative Method: Importing Through a Family
Another approach is to import the DWG into a Revit family first:
- Create a New Family: In Revit, create a new family. Choose a template appropriate for the type of geometry you are importing (e.g., Generic Model, Furniture, etc.).
- Import the DWG: Within the family editor, go to the "Insert" tab and use either "Import CAD" or "Link CAD" to import the DWG file, using the same settings described above.
- Load into Project: Once the geometry is imported into the family, load the family into your Revit project. You can then place instances of the family as needed.
Important Considerations
- Clean up the DWG: Before importing, clean up the DWG file in AutoCAD or a similar CAD program. Remove any unnecessary layers, lines, or objects. This will simplify the import process and improve performance.
- Layer Management: Think carefully about layer mapping and visibility. You can control the visibility of layers in the imported DWG through the Revit Visibility/Graphics Overrides settings (VG).
- Performance: Importing complex DWG files can significantly impact Revit's performance. Use linked files when possible, and consider breaking up large DWG files into smaller, more manageable pieces.
- Units: Double-check and verify the units are set correctly.
In summary, importing DWG files either directly or via a family is the primary way to bring geometry into Revit, requiring careful attention to settings and consideration for the impact on model performance.
