Revit 2019.1 APIArc..::..Radius Property Arc Class See Also Returns the radius of the arc.Namespace: Autodesk.Revit.DBAssembly: RevitAPI (in RevitAPI.dll) Version: 19.0.0.0 (19.1.0.0)SyntaxC#public double Radius { get; }Visual BasicPublic ReadOnly Property Radius As Double GetVisual C++public: property double Radius { double get (); }See AlsoArc ClassAutodesk.Revit.DB Namespace