For Curtain Panel families, the horizontal spacing of the driving mesh. 
   Namespace:   Autodesk.Revit.DB  
  Assembly:   RevitAPI  (in RevitAPI.dll) Version: 2015.0.0.0 (2015.0.0.0) 
Syntax
Exceptions
| Exception | Condition | 
|---|---|
| Autodesk.Revit.Exceptions InvalidOperationException | Thrown if this family is not the owner family of a curtain panel family document. |