The soft shadows precision value. 
   Namespace:   Autodesk.Revit.DB  
  Assembly:   RevitAPI  (in RevitAPI.dll) Version: 2015.0.0.0 (2015.0.0.0) 
  Since:  2013 
Syntax
Remarks
 Increase this value when the edges of soft shadows appear to be speckled, rather than smoothly blurred. 
 Exceptions
| Exception | Condition | 
|---|---|
| Autodesk.Revit.Exceptions ArgumentOutOfRangeException | When setting this property: The soft shadows precision value is not valid. The valid range is 1 to 10. | 
| Autodesk.Revit.Exceptions InvalidOperationException | When setting this property: The RenderingQualitySettings does not use custom quality currently. To use custom quality, set RenderingQuality property to RenderingQuality.Custom. -or- When setting this property: Shadows are not enabled. |