For Revit users with the AEC Collection, sometimes available topographic data from an engineer is too cost prohibitive, or just not available yet for a project. That’s where a great website comes in called www.cadmapper.com With cadmapper, you can generate free CAD files of up to 1km2 containing the project’s topo data to use for Revit. In addition, you can also use it for other site context geometry including roads, paths, buildings, and other features!
Once you generate the file, which will come in the form of a layered DXF, simply open it in AutoCAD. If you do it this way, you will notice that the DXF file uses the Decimal units. That’s on purpose so that the file scales appropriately. Do not change the units!
While in AutoCAD, adjust the view so that it is in 3D and that the Visual Style makes it easy to see the topo mesh versus other geometry. Notice how it’s divided into some pretty big chunks of squares. Those polygons will also make the Revit topo seem chunky when converted. We will want to smooth that. Start by selecting on the topo portion of the mesh, then Right Click with your mouse button.
Choose Smooth More to enable a tighter, smoother mesh. Then choose Refine Mesh to actually add more squares (polygons) to the mesh, which will make it smoother. You can continue this work flow as much as you like, however the file size will grow and it could make it more and more difficult to load into Revit.
Once you are happy with the layout, save it as a DWG, as shown here:
Now it’s time to load it into Revit!! Link the DWG file in using similar settings as below. The key setting to change is the Import Units. Ensure that they are set to “meter”, as that was the format that the original DXF was created in. If this is not done, the file will not load to scale, even if it had remained set to Auto-Detect. Your file may then look something like this when in a 3D view:
Once it shows in a 3D view, go to the Massing & Site tab > Toposurface command and select it:
This will open the Contextual Ribbon. Select Create from Import, and then Select Import Instance. This will allow you to select the DWG file and use its geometry to generate the points needed for the Revit toposurface.
Select the DWG and a dialog box will appear. The only Layer that is required for the toposurface, is Contours. All others can be deselected. Select OK when done.
Congratulations!! A toposurface based on your linked DWG file has been created!
Be sure to hide or unload the dwg file now if you no longer need to reference it. However, packed into this file are also other great meshes for site context, such as roads, buildings and more! If you plan on doing any renderings, these can become especially useful! Perhaps someone will write a future blog post on that? I wonder…
About the AuthorFollow on Linkedin More Content by Kenniston Crane