Revit Material Assignment Series – Part 2, Topography

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In Revit, when a building pad is added within the boundaries of a Toposurface, it will create a cut or fill edit (cut example shown here). By default, the material assigned to the Toposurface is assigned to the new sides and flat bottom of the area being cut.

In the following image, the building pad has been hidden so the "Grass" material on the bottom can be seen.

This new geometry is essentially a subregion. It can be selected (see image below) and have its material changed. It is, however, a single entity (all the sides and the bottom).

Notice the material has been changed for the selected automatic subregion created by the Building Pad.

If the Building Pad is ever deleted, the subregion goes away, and the Toposurface heals.

On a related note... with this knowledge, those who use Enscape can avoid the problem where the height of the grass grows through the Building Pad or Floor elements, as shown below.

Here is an example where the subregion material has been applied, and the grass is obscured correctly!

Here is a link to Part 1 in this series: https://forums.autodesk.com/t5/autodesk-community-voices/revit-material-assignment-series-part-1-by-...