As we know, the coordinate systems in AutoCAD Civil 3D and Revit are very different. This difference makes coordination between Revit and AutoCAD Civil 3D really hard.
The reason is that for any given point, Civil 3D has a number of real world GIS coordinate systems, as shown below.
Figure 0-1 The GIS coordinate system list of AutoCAD Civil 3D.
However, Revit works with either Project Internal Coordinates or Shared Coordinates, as shown below. These coordinates generally are not the real world coordinates.
Figure 0-2 The coordinate system options for Revit.
Therefore, if you bring the Revit model into the Civil 3D drawing, they will not be aligned. For this alignment to work, you need to use the Civil 3D drawing and set up real world coordinates in Revit.
The following steps explain how to do this.
- Open the surface model in C3D, then export it to Vanilla AutoCAD file.
- As I am using 2018 AutoCAD Civil 3D and Revit 2017, I need to use command Exporttoautocad2013 to convert the drawing to AutoCAD 2013 format, for the same version of Civil and Revit, you can just use EXPORTTOAUTOCAD.
Figure 2-1 Convert Civil drawing to AutoCAD drawing.
Figure 2-2 Save drawing.
Next, you will import the DWG file into Revit to align the coordinates.
3. Open the Revit file. I am using the sample file, as shown below.
Figure 3-1 Revit model.
4. Insert the AutoCAD drawing in Revit via Link CAD. While inserting, make sure you select the Auto – Center to Center position, as shown below.
Figure 4-1 import AutoCAD drawing to Revit.
5. Once the civil file is inserted, the tin surface will appear in the Revit model, as shown below.
Figure 5-1 Revit model with Civil 3D surface
6. Activate the Site view to switch to the plan view, as shown below:
7. Select the tin surface anywhere and then click Share Site in the Properties window; the Share Coordinates dialog box will be displayed.
8. In the dialog box, select Acquire the shared coordinate system from XXXXXX.dwg, as shown below.
Figure 8-1 Share Coordinate in Revit
9. Click Reconcile.
Next, you will use various Revit tools to align the North direction of the tin surface with that of the Revit model.
10. Align the North direction of the tin surface with the Revit model by rotating the tin surface.
Figure 10-1 Rotate Civil drawing to align the North direction
11. Move the centre of rotation point to the coordination point in Revit.
Figure 11-1 Move the Civil surface in Revit, and the cogo point will match the project base point in Revit
Next, you will disable the DWG file in the Revit model to hide it.
12. Enter VG to display the Visibility Graphics dialog box.
13. On the Model Categories tab, under Site, clear the Survey Point tick box, as shown below.
Figure 8-1 Disable Survey Point