By Dennis Collin
For many years Revit has had the ability to work with site survey drawings and be able to use such information such as contour data and other 3D elements to form topographic forms to show a building within a site context. However, many agencies use Autodesk Civil 3D and there is a requirement for users to directly import Civil 3D surfaces into Revit directly, using the forms that Civil 3D has defined.
This has been possible since Revit 2019 with the relatively new function, Link Topography. This brings in a linked Civil 3D surface. Like other linked files, Revit can acquire coordinates from the Civil 3D link as well as colour up the surface to better present features like footpaths, roads, building pads and other site features.
The linking process is conducted via the Autodesk Construction Cloud (BIM 360 Docs). A project needs to be created, and the Civil 3D surface model published to this location. Anyone needing to access the file would need to be granted permissions to view and link the file.
Choosing Link Topography allows the user to select the published surface from the ACC project and link the file in as a reference. The surface will be mapped to a user selected toposolid object style and level reference.
Upon linking, a message will appear asking whether the Revit model should adopt the Civil 3D’s model location or position the link centre-to-centre, with the coordination operation to be performed later.
Once linked the topography can be reloaded or removed from the Topography tab on the manage links dialogue.
The Topography typically is represented by a single toposolid style, but Civil 3D’s surface sub-components can be selected with the ‘magic’ TAB key and alternate toposolid styles can be assigned with the type selector drop-down.
Should the Civil 3D surface change, the linked topography can be reloaded, and the subsequent toposolid style assignments will be maintained and respected.