Creates a runoff surface by extending a face. 
Access
On the 
Core/Cavity tab, click 
 Extend Runoff Surface
 Extend Runoff Surface. 
Note: Extrude Runoff Surface, Bounded Runoff Surface, Radiate Runoff Surface, and Extend Runoff Surface are grouped. Click the down arrow to show all the options. 
 - Extend Type 
- 
- Select Extend along Tangent to create a tangent surface. 
- Select Extend along Rule to create a ruled surface. 
 
- Face 
 Select the face to define the surface. Select the face to define the surface.
- Edges 
 Select one or more edges to define the surface. Select one or more edges to define the surface.
- Automatic edge chain 
-  Sets the edge selection preference. Select to include all tangent edges automatically when selecting an edge to define the surface. To select only the indicated edges, clear the check box. 
- Preview 
- 
   Provides a preview of the surface based on the current selections.