Revit Toposolid: Create, Edit, Cut & Grade

Toposolid is the Revit 2024 and newer tool for modeling site topography. It replaced the older Toposurface workflow and gives terrain a solid volume, compound layers, shape-edited points, subdivisions, cut geometry, excavation workflows, graded regions, and cut/fill reporting.

The fastest way to create a Revit Toposolid is to go to Massing & Site > Toposolid, choose either Create from Sketch or Create from Import, then use Modify Sub Elements and Add Point to shape the terrain. For survey data, use a 3D DWG, DXF, DGN, or CSV points file so Revit can read real elevation data.

What Changed in Revit 2024, 2025, and 2026?

If you are coming from Revit 2023 or earlier, the main change is simple: Toposurface and Building Pad are no longer the main site tools in Revit 2024 and later. Toposolid is now the primary topography element, and building pad workflows are handled with cuts, excavations, floors, foundations, walls, voids, subdivisions, and graded regions.

Version	Important Toposolid Notes
Revit 2024	Toposolid replaces Toposurface for new topography workflows. Building Pads are removed, so terrain cuts are handled with cutting elements and voids.
Revit 2025	The Excavate workflow improves how floors, walls, foundations, and in-place elements remove volume from a Toposolid.
Revit 2026	Toposolid subdivisions, linked topography accuracy, graded region volume accuracy, point thresholds, and void-cut stability were improved.

For most projects, this means you should model existing terrain as a Toposolid, use Graded Region for proposed grading, and use Excavate or Cut Geometry for building pads, basements, retaining walls, shafts, pools, and other subtractions.

Best Method to Create a Toposolid

Method	Use It When	Best For
Create from Sketch	You do not have survey data, or you are creating a simple conceptual site.	Small projects, quick massing, early design.
Create from CAD	You have a DWG, DXF, or DGN with 3D contour lines.	Architectural site plans based on civil/survey contours.
Create from CSV	You have a points file with coordinate and elevation data.	Survey points, cleaner terrain generation, large sites.
Generate from Toposurface	You are upgrading or reusing an older Revit file.	Revit 2023 and older models.
Link Topography	Your civil/topography data is managed outside the building model.	Coordinated BIM workflows with Autodesk Docs topography links.

If you want the most reliable model, start from clean survey data. If you only need a visual terrain surface for presentation or early design, the sketch method is usually enough.

Before You Start: Prepare the Site Data

Most Toposolid problems start before the Toposolid is created. Check these items first:

• Use a site or 3D view. Toposolids may be hidden in some plan views, so use a site plan or a 3D view when creating or checking the terrain.
• Use real 3D data. CAD contours must have correct Z elevations. Flat 2D contour lines do not create a meaningful Toposolid.
• Do not link CAD as Current View Only if you plan to create a Toposolid from it.
• Coordinate the Project Base Point and Survey Point before linking survey files. Wrong base elevations can place the Toposolid far above or below the building.
• Select only the correct contour layers. Extra layers, zero-elevation lines, or non-terrain objects can create incorrect dips or spikes.

In Revit 2026, Autodesk lists the default point threshold for native and linked Toposolids as 20,000 points, with a configurable range from 10,000 to 50,000 in the Revit.ini settings. A higher threshold can improve accuracy, but it can also slow editing and navigation on large terrain models.

Method 1: Create a Toposolid from Sketch

Use this method when you want to create a Toposolid manually inside Revit. It is the easiest option for a simple site model, schematic terrain, or a small project without survey files.

1. Open a site plan or 3D view.
2. Go to Massing & Site > Model Site.
3. Open the Toposolid menu and click Create from Sketch.
4. Use the Draw tools to sketch a closed boundary.
5. Click Finish Edit Mode.

After creating the flat boundary, shape the surface with elevation points:

6. Select the Toposolid.
7. Click Modify | Toposolid > Shape Editing > Add Point.
8. Enter the elevation value in the Options Bar.
9. Place points along the terrain where the elevation changes.
10. Use Modify Sub Elements to adjust existing points and edges.

Tip: Use Absolute when you want points placed at one fixed elevation. Use an offset option when the point should be measured relative to another datum or surface condition.

Method 2: Create a Toposolid from CAD

This is the best method when you receive site contours from a surveyor, civil engineer, Cadmapper, AutoCAD, Civil 3D, or another source that can export 3D contour data.

1. Open a site plan or 3D view.
2. Go to Insert > Link > Link CAD.
3. Select the DWG, DXF, or DGN file.
4. Make sure Current View Only is not selected.
5. Choose the correct positioning option for your coordinate workflow.
6. Click Open.

Then generate the Toposolid from the linked file:

7. Go to Massing & Site > Toposolid.
8. Click Create from Import.
9. Click Create from CAD.
10. Select the linked CAD instance in the drawing area.
11. In the layer dialog, select only the contour layers that contain correct elevation data.
12. Click OK.

Important: If the DWG contours are real-world elevations and your Revit project base is not coordinated, the Toposolid may appear at the wrong height. Set the Project Base Point and Survey Point before linking, or create a level at global 0.00 and link the CAD file relative to that level.

Method 3: Create a Toposolid from CSV Points

A CSV file is often cleaner than a crowded CAD file because it contains only point coordinates and elevations. Use this method when your surveyor can provide point data directly.

1. Open a 3D view.
2. Go to Massing & Site > Toposolid > Create from Import.
3. Click Create from CSV.
4. Select the points file.
5. Choose the correct unit format, such as decimal feet or meters.
6. Click OK and let Revit generate the Toposolid.

For very large sites, split the survey into smaller logical areas if you need more point accuracy or smoother editing performance. In Revit 2026, the maximum native Toposolid point threshold can be adjusted in Revit.ini, but pushing the threshold higher can make the model heavier.

Method 4: Convert a Toposurface to Toposolid

Use this method when you are updating a Revit 2023 or older project. It lets you keep the existing terrain data instead of rebuilding the site from scratch.

1. Open the Revit file that contains the old Toposurface.
2. Select the Toposurface.
3. Go to Modify | Topography > Surface.
4. Click Generate Toposolid.
5. Select the base level and Toposolid type.
6. Click OK.

After conversion, compare the new Toposolid against the original Toposurface before deleting anything. Keep a backup view or hidden reference until you confirm the elevations, perimeter, and contour behavior are correct.

Edit a Toposolid After Creation

After the Toposolid exists, most edits happen through Modify Sub Elements, Add Point, Delete Point, and boundary-related tools. This is where you adjust slopes, berms, ramps, drainage areas, roads, and level pads.

1. Select the Toposolid.
2. Click Modify Sub Elements.
3. Select a point, edge, or subelement.
4. Enter the new elevation value or move the selected point in the model.
5. Use Add Point where the terrain needs more definition.
6. Use Preview Points if you want elevation points visible while reviewing the model.

Do not add unnecessary points. A Toposolid with fewer well-placed points is usually easier to control than one with thousands of noisy survey points.

Control Contour Lines

Contour lines are controlled through the Toposolid type. Use them to show elevation intervals clearly in site plans and 3D views.

1. Select the Toposolid.
2. In Properties, click Edit Type.
3. Under Graphics, click Edit beside Contour Display.
4. Set the contour intervals, elevation values, and subcategories.
5. Click OK.

To change contour line appearance globally, go to Manage > Object Styles, expand Toposolid, and edit the subcategory line weight, line pattern, and material. To change only one view, use Visibility/Graphics with the shortcut VV.

Split a Toposolid

Split a Toposolid when you need separate terrain elements for phasing, materials, ownership, roads, courtyards, or independent editing. Splitting is also useful when a large imported terrain is too heavy to manage as one object.

1. Select the Toposolid.
2. Go to Modify | Toposolid > Shape Editing.
3. Click Split Element.
4. Sketch the split boundary or split line.
5. Click Finish Edit Mode.

Subdivide a Toposolid for Materials and Surface Areas

A subdivision lets you mark a surface area on the host Toposolid without replacing the entire terrain. Use subdivisions for grass, roads, gravel, pavement, planting beds, paths, and other surface finishes.

1. Go to Massing & Site > Toposolid.
2. Click Sub-Divide.
3. Sketch the subdivision boundary on the host Toposolid.
4. Click Finish Edit Mode.
5. Select the subdivision and assign the correct Toposolid type or material behavior.

In Revit 2026, subdivisions were improved so they follow the host Toposolid geometry more closely. They can also use offsets; a negative offset can recess into the host and report excavation volume through the subdivision properties.

Change Toposolid Material and Layers

A Toposolid type uses a compound structure similar to floors. This means you can add layers such as soil, gravel, sand, rock, and finish materials, then see those layers when the terrain is cut in section.

1. Select the Toposolid.
2. In Properties, click Edit Type.
3. Click Duplicate before changing the type.
4. Under Construction, click Edit beside Structure.
5. Insert, delete, reorder, or edit layers.
6. Assign materials and thicknesses.
7. Click OK.

Tip: Duplicate the type first. If you edit the original type, every Toposolid using that type may change across the project.

Cut or Excavate a Toposolid

In Revit 2024 and newer, the old Building Pad workflow is replaced by cutting and excavation methods. The best method depends on your Revit version and the element doing the cut.

Goal	Recommended Workflow
Cut terrain with a floor, wall, or foundation	Use Excavate in Revit 2025 or newer, or use Cut Geometry where appropriate.
Create a complex basement, pool, trench, or tunnel cut	Use an in-place mass or generic model void, then cut the Toposolid.
Revit LT workflow	Use basic model elements or in-place wall voids where available.
Several separate void shapes	Place multiple forms inside one in-place element, then perform the cut once.

To cut a Toposolid with a void form:

1. Go to Architecture > Component > Model In-Place.
2. Choose a suitable category, such as Generic Models or another category that works in your project workflow.
3. Create a Void Form, such as a Void Extrusion.
4. Adjust the void so it intersects the Toposolid.
5. Click Cut Geometry.
6. Select the Toposolid, then select the void form.
7. Finish the in-place model.

If the cut fails in Revit 2026, check whether Cut Void Stability is appropriate for the model. Autodesk added this setting to improve the chance of successful Toposolid cuts by applying a small shift to the cut geometry when needed.

Use Graded Region for Existing and Proposed Terrain

Use Graded Region when you need to compare existing and proposed terrain and report cut/fill quantities. This is the correct workflow for earthwork studies, slope revisions, grading options, and site phasing.

1. Create at least two phases, such as Existing and New Construction.
2. Select the existing Toposolid.
3. Set Phase Created to Existing.
4. Open a site plan that displays the Toposolid.
5. Go to Massing & Site > Graded Region.
6. Choose whether to copy all points or perimeter points only.
7. Select the existing Toposolid.
8. Edit the new graded region using Modify Sub Elements and Add Point.

Choose all points for a more accurate copy of complex terrain. Choose perimeter points only for simpler grading studies where performance and clean editing matter more than exact survey point density.

Calculate Cut and Fill Volumes

After creating a graded region, you can report cut and fill values in a Toposolid schedule. Autodesk states that Toposolid cut/fill values are approximate, so use them for design coordination and quantity studies, then confirm final earthwork quantities with the project requirements and civil documentation.

1. Go to View > Schedules > Schedule/Quantities.
2. Select the Toposolid category.
3. Add fields such as Phase Created, Cut, Fill, and Net Cut/Fill.
4. Set the schedule phase and phase filter so the existing site does not confuse the proposed grading results.
5. Sort, group, and total the values as needed.

In Revit 2026, Autodesk improved graded region volume accuracy so volume is calculated within the boundary of the new Toposolid instead of including extra volume beyond that boundary.

Place Elements on a Toposolid

Toposolids can host or interact with site elements such as planting, furniture, rocks, walls, foundations, floors, and other model components. For presentation views, switch to Consistent Colors or another visual style that makes hosted elements easy to see against the terrain.

1. Load the families you need from Insert > Load Autodesk Family or your office library.
2. Go to Architecture > Component.
3. Select the family type.
4. Place the component on or near the Toposolid as required by the family behavior.

Troubleshooting Toposolid Problems

Toposolid Is at the Wrong Height

This usually happens when CAD contours are placed at real-world elevation but the Revit project base level is not coordinated. Check the Project Base Point, Survey Point, linked CAD positioning, and whether you need a global 0.00 level for the linked file.

Toposolid Has Spikes or Drops to Zero

The imported file probably includes incorrect layers, objects with zero elevation, or non-contour geometry. Recreate the Toposolid using only the correct contour layers, or use an elevation/3D view to select and delete outlier points.

Create from Import Is Too Slow

Reduce the source data before importing, split the site into smaller files, simplify the resulting Toposolid, or adjust the Revit 2026 point threshold only when the project really needs higher accuracy.

Excavate Does Not Work

Check for duplicate Toposolids, overlapping cutting elements, incorrect phasing, or a phase filter that hides the expected result. In Revit 2025 and newer, Excavate is the cleaner workflow for many building pad replacements, but the cutting element still needs to intersect the Toposolid correctly.

Can You Create a Toposolid from IFC?

Not directly. As of Autodesk’s July 2026 guidance, Revit cannot directly generate a Toposolid from an imported IFC. The practical workaround is to export the terrain to DWG, or extract 3D point coordinates from IFC data into a CSV file and create the Toposolid from that CSV.

FAQ

What is a Toposolid in Revit?

A Toposolid is the Revit 2024 and newer site terrain element. It represents topography with elevation points, contours, volume, layers, subdivisions, and cutting behavior.

How do you create a Toposolid in Revit?

Go to Massing & Site > Toposolid. Use Create from Sketch for manual terrain, Create from Import for CAD or CSV survey data, or Generate Toposolid when converting an old Toposurface.

How do you create a Toposolid from CAD in Revit?

Link a 3D DWG, DXF, or DGN without Current View Only, then go to Massing & Site > Toposolid > Create from Import > Create from CAD and select the correct contour layers.

How do you cut a Toposolid in Revit?

Use Excavate in Revit 2025 or newer where available, or use Cut Geometry with floors, walls, foundations, in-place elements, masses, generic models, or void forms depending on the project and Revit version.

How do you calculate cut and fill for a Toposolid?

Create a graded region from an existing Toposolid, edit the proposed terrain, then create a Toposolid schedule with Cut, Fill, and Net Cut/Fill fields.

How do you change Toposolid material in Revit?

Select the Toposolid, click Edit Type, duplicate the type, then edit the Structure layers and assign the required materials. For surface-only zones, use subdivisions.

Final Workflow

For a clean Revit Toposolid workflow, start with coordinated survey data, create the terrain from sketch, CAD, or CSV, verify the elevations, then edit points and contours before adding subdivisions, layers, cuts, excavations, and graded regions. If cut/fill matters, set the existing Toposolid to an earlier phase first, create a graded region in the proposed phase, and report the results with a Toposolid schedule.

For related workflows, see our guides to site plans in Revit, importing CAD into Revit, Cut Geometry in Revit, Revit phases, and exporting Revit schedules to Excel.