How to Import surface in Revit?

To import a surface, typically a Toposurface, into Revit, you can create it from imported data, commonly from a CAD file like DWG.

The most common method involves linking a DWG file containing 3D data (like 3D points, contours, or mesh) and then using that data to generate a Revit Toposurface.

Steps to Import a Surface from a Linked DWG

Here's how to create a Toposurface in Revit based on a linked DWG file:

1. Link the DWG File: First, link the CAD file containing the surface data into your Revit project. Go to the Insert tab, select Link CAD, choose your DWG file, and adjust positioning settings as needed.
2. Create Toposurface from Import: Once the DWG is linked and visible in a relevant view (like a Site Plan or 3D view), you can create the toposurface.
   • Go to the Massing & Site tab.
   • In the Model Site panel, click Toposurface.
   • On the Modify | Edit Surface ribbon tab, under the Tools panel, choose "Create from Import".
   • Select "Select Import Instance".
3. Select the Linked DWG: Click on the linked DWG file in the Revit view.
4. Specify Layers: A dialog box will appear listing the layers from the selected DWG file. These layers potentially contain the data needed to create the toposurface.
   • Click "Check None" first to deselect all layers.
   • Then, select only the layers containing the toposurface data (e.g., layers with contour lines, 3D points, or breaklines). Ask your CAD source if you are unsure which layers contain the relevant data.
5. Finish Creation: Click OK in the layer selection dialog. Revit will process the selected layers and display the generated toposurface preview. Click the green checkmark (Finish Surface) on the ribbon to finalize the toposurface creation.

Revit uses the 3D information on the selected layers to place points and define the elevation of the toposurface.

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This process is directly based on importing data from a linked external file as a source for creating a native Revit Toposurface element.