In our last article on the GovDesignHub, the team at Repro Products explained some of the updates and new features that were added in the latest update to Autodesk’s Revit solution. While there have been significant new capabilities and functionality added to this revolutionary Building Information Modeling (BIM) solution, one of the biggest updates is the new Toposolid tool.

What is the Toposolid tool?

Formerly known as the Toposurfaces tool, the Toposolid Tool defines a topographical element using defined elevation points or imported CAD or CSV files. Toposolids support surface patterns of the assigned material and can be cut by other model geometry. A user can also create a toposolid by sketching a boundary and adding elevation points within the boundary.

Here is a detailed look at the changes and improvements to the Toposolid functionality and tips for using it effectively.

The Massing and Site Tab

The Massing and Site Tab has been revised. Toposurfaces have been killed and replaced by Toposolid.  The Split/Merge surfaces tools are also gone.  The Subregion tool has been replaced by Sub-Divide.  The way you create site elements is completely different. See below…

New Toposolid Tool

The old toposurface tool was only a “surface” element. It had no depth, and you couldn’t set a thickness.  I always wanted the toposurface to be more like a system family such as floors.  Behold, the new toposolid tool works just like floors. Create your sketch in Sketchmode.

Use Modify Sub Elements in a similar way to Roofs and Floors. Add points at specific heights to create the slopes.

The points contextual menu is a bit different from the standard floors and roofs you are used to. This new menu has been available since Revit 2023.1, but most users didn’t notice.  You can pick which origin point you want to use (Internal Origin, Project Base Point or Survey Point).  When adding a point, you can either pick Along Surface or Absolute Height.

You can still import a CAD or CSV file to automatically create the shape of the topography. This tool now works with concave site shapes.

You can modify the structure of the toposolid with materials of various thicknesses. Here are a few examples from Revit’s new default template:

That means you can create fun site elements (such as lakes) without using floors. 

Create Toposolid from Toposurface

You can only access the old toposurface tool when opening models from earlier versions.  When selecting a toposurface, use Generate Toposolid to convert to the new tool. The old toposurface remains; you’ll have to manually delete it. To be safe, you can keep it in the archives.

As a warning, when generating a toposolid, building pads are ignored completely and subregions are changed into subdivisions.

Subdivision on Toposolid

Subregions in Revit 2023 have been replaced by Sub-Divide. The base idea is the same: draw boundaries over the toposolid. Similar to sub-regions, you can extend the boundaries beyond the limit of the toposolid without receiving a warning.

Sub-Divisions are placed on top of the toposolid. You can then pick a material and set a thickness in the instance properties. Sub-Division has a thickness instance parameter. You cannot use a negative value or try to “recess” the subdivision into the toposolid.  It must be a positive value.

There is another parameter called Inherit Contours. It allows you to decide if you want to see the contours on the subdivision or not. Activating this option doesn’t affect the geometry of the subdivision.

Mass Void Excavation Form

Building pads are gone. Instead, Autodesk recommends using the Massing tool to create void geometry. They allow you to create more complex shapes. In this example, we create a void shape for a parking driveway.

Mass Void Excavation Form

Building pads are gone. Instead, Autodesk recommends using the Massing tool to create void geometry. They allow you to create more complex shapes. In this example, we create a void shape for a parking driveway.

You can decide to have a toposolid type with lots of contours. However, the contours are not visible when editing the points.

And maybe you want a water toposolid without any contours.

Cut Toposolid

The new toposolid can be cut using multiple categories, including walls, floors, other toposolid, structural foundations, etc.

In this example, the toposolid is cut to accommodate the foundation wall and footing.

The volume of the toposolid accurately reflects the subtraction of these elements.

Enable Slab Edges on Toposolid

You can use the Slab Edge feature on toposolids. This can be used to create curbs.

However, there is a big caveat! You cannot use this tool in subdivisions, or on very complex shapes. In the example above, you would like to place the slab edge on the subdivision, but Revit won’t allow it.

Split Toposolid

You can now use the Split tool on the new toposolid feature. Since toposolids are like floors, you can switch the composition entirely and have lakes, concrete pads, and other site components while keeping the original topography points.  Be careful, though. Once the toposolids are split, you can’t merge them.

Lined Topography Becomes Toposolid

If you link a Topography from Civil 3D, you must now create a toposolid by picking a base level and a family type.

Enable Toposolid to Host Floor-based Family

You can use floor-based families in the new toposolid category.

Toposolid Graded Region

You can use the same Graded Region tool on toposolid. The workflow is simple: select the toposolid, use the Graded Region, then modify the toposolid in the “new” phase.

After you are done modifying the topography points, you should notice Net cut/fill values in the instance properties. These are quite helpful.   Be careful: apparently, these values are not always accurate. If the sketch boundaries of the new toposolid are different, the calculated volumes will not be correct.

Point Visual Management for Slab Shape Editor

When you modify the Sub Elements of a toposolid, you can decide if you want a preview of all the topography points or not. Activate the preview this way:

You can see the difference when the option is active. 

This feature is available not only with toposolid but also with floors and roofs.

If you would like to learn more about all of the new features in Revit 2024, click HERE.