Toposurface Subregions

Toposurface subregions are areas that you sketch inside existing toposurfaces. For example, you can use subregions to draw parking lots on a graded surface, roads, or islands. Creating a subregion does not result in separate surfaces. It merely defines an area of the surface where you can apply a different set of properties, such as material.

To create a subregion

1. Open a site plan that displays a toposurface.
2. Click Site tabModel Site panel (Subregion).

   Revit LT enters sketch mode.

3. Click (Pick Lines) or use other sketch tools to create a subregion on the toposurface.

To modify subregion boundaries

Example

The following image shows a toposurface that has a subregion, shown in gray.

Related topics

• Splitting a Toposurface
• Graded Regions
• Toposurface and Subregion Properties