The ground plane should be an Element of type Level. This method checks to confirm that an ElementId is for a Level element.

Namespace: Autodesk.Revit.DB.Analysis
Assembly: RevitAPI (in RevitAPI.dll) Version: 22.0.0.0 (22.1.0.0)
Since: 2011

Syntax

C#
`public static bool CheckGroundPlane( Document ccda, ElementId groundPlaneId )`

Visual Basic
`Public Shared Function CheckGroundPlane ( _ ccda As Document, _ groundPlaneId As ElementId _ ) As Boolean`

Visual C++
`public: static bool CheckGroundPlane( Document^ ccda, ElementId^ groundPlaneId )`

groundPlaneId: Type: Autodesk.Revit.DB ElementId
The element id to be checked to confirm that it is suitable to be a ground plane (i.e., that it is a level) or that it is invalidElementId. Setting ground plane with invalidElementId will lead to the ground plane being "reset".

True if the input element is a level or invalidElementId, false otherwise.

Exceptions

Exception	Condition
Autodesk.Revit.Exceptions ArgumentNullException	A non-optional argument was null