Exporting a TIN Surface .DWG to a .DXF in Civil 3D

Civil 3D Workflow

Isolate the Surface Triangles in Civil 3D

First, you will modify the surface style to display only the 3D triangle faces.

1. Open your project in Civil 3D. Ensure the drawing is georeferenced in the correct coordinate system.
2. Select the TIN surface in the model space.
3. Right-click the selected surface and choose Edit Surface Style.
4. In the Surface Style dialog box, navigate to the Display tab.
5. Turn off the visibility for all components (like Borders and Contours) by clicking the light bulb icon, leaving only Triangles turned on.
6. Click OK. Your surface should now display only as a triangular mesh.

Convert the Surface to 3D Faces

The TIN surface object must be converted into basic 3D face objects that other software can read. This is done using the EXPLODE command twice.

1. Select the triangulated TIN surface again.
2. Type the command EXPLODE and press Enter. This converts the complex TIN surface into a Block Reference.
3. Select the newly created Block Reference.
4. Type EXPLODE and press Enter again. This second explosion converts the block into individual 3D Faces, which Propeller can interpret.

Before: Contours and border	After: Triangles only

Export the 3D Faces to DXF

Finally, export the new 3D faces to a DXF file.

1. Click the Civil 3D application icon (the "C" in the top-left).

2. From the dropdown menu, go to Save As > Other Formats.

   

3. In the "Save Drawing As" window, set the Files of type to AutoCAD 2018 DXF (*.dxf).
4. Navigate to your desired save location.
5. Before saving, click the Tools dropdown in the top-right of the window and select Options.
6. In the Save as Options dialog, go to the DXF Options tab. Check the box for Select objects and ensure the format is set to ASCII. Click OK.
   • Why ASCII? The ASCII format ensures maximum compatibility with other platforms.

7. Click Save. You will be returned to your model space to select the objects for export.
8. Your cursor will now be a selection box. Click and drag a window around the entire surface to select all its 3D faces, then press Enter.

The .DXF file containing the 3D faces will be saved in your selected folder and is ready for upload to Propeller.

I still can't do it!

We wrote these articles to equip you with everything you need to get the job done on your own, but we understand that sometimes this isn't sufficient.

If you're stuck, you can connect with our support team by clicking the question mark button at the top right corner of your user portal.