Creating Accurate Toposolids in Revit 2025

With the new object type in Revit 2024 and 2025, it is helpful for Enscape users to have a good understanding of how to create an accurate surface from a civil CAD file. This post will cover two primary options while highlighting the slight difference in accuracy. Following these steps will result in a more accurate toposurface in Revit and Enscape!

Included with this article is a video highlighting the process of exporting an AutoCAD Civil 3D surface for use in Revit. Revit users are not often experienced with Civil 3D and vice versa. Thus, consider sharing this article with your civil team.

Civil CAD files – elevated contours

The most common, yet least accurate, method of creating a Revit toposolid in Revit is by using a civil CAD file defined by contours at the correct elevation. Revit will find points along these contours and use those points to create the toposolid. The limitation is there is often a lot happening between the contours that is lost. For example, spot elevation, tie-ins to stoops, and more. However, as shown in the video, the overall accuracy is still decent.

Civil CAD files – triangulated surface

A more accurate option is to ask your civil team for a triangulated surface. As shown in the image below for the same surface, there is a lot more detail. Revit has a lot more lines to add points to. In the video, you will clearly see how the contours more closely match the contours from AutoCAD Civil 3D.

Accurate contours in Revit

Once the civil CAD file has been linked in and the Revit toposurface has been created, the contour display for the toposolid can be adjusted. Here, you want to match the contour spacing in the civil CAD file. The Start value should be set to zero so the contours are created from sea level. This will make them graphically and numerically align.

The following image shows the contour in Civil 3D is set to 55.

The next image is from Revit, showing the contours have the same values.

Results in Enscape

By default, the surface may look triangulated and choppy, as shown in the image below. This is the civil 3D surface defined by a toposolid in Revit. The sun has been adjusted to be early in the morning to exaggerate the issue.

In Revit, on the Massing and Site tab, the Toposolid Smooth Shading can be toggled on to help alleviate the choppy look.

Notice how the ground surface looks much smoother now.

Here are two more views within Enscape showing off this large complex site now clearly and accurately defined within Revit.

Toposolid accuracy video

To make the entire creation process within Revit clear, I created this video highlighting two methods of creating the toposolid: from contours and triangulated surfaces.

Another important aspect of managing locations within Revit is Shared Coordinates. I have a video series that provides an easy-to-understand overview. This method works on local and BIM 360 projects.

Enscape context feature

While on the topic of developing sites, it is helpful to note that Enscape can generate an early-phase site context model. Enscape's Site Context feature, which uses OpenStreetMap data, immerses your design within the urban fabric it is meant for.

Instead of linking a map or plat drawing to your design software and spending a couple of hours outlining and extruding shapes to represent existing buildings around the project, you can achieve similar results in minutes with Site Context.

This feature might only be used at the beginning of a project, while others might find the level of detail adequate for the entire project. To learn more about its best practices, you can read my article on the topic.

Conclusion

Creating an accurate ground surface within your CAD/BIM tool is important to ensure your building is well coordinated and also improves the visualization experience and credibility of a project’s design proposal.