The tangent vector at the start of the curve.

Namespace: Autodesk.Revit.DB
Assembly: RevitAPI (in RevitAPI.dll) Version: 22.0.0.0 (22.1.0.0)
Since: 2014

Syntax

C#
`public XYZ StartTangent { get; set; }`

Visual Basic
`Public Property StartTangent As XYZ Get Set`

Visual C++
`public: property XYZ^ StartTangent { XYZ^ get (); void set (XYZ^ value); }`

This must be a nomalized unit vector.

Exceptions

Exception	Condition
Autodesk.Revit.Exceptions ArgumentNullException	When setting this property: A non-optional argument was null
Autodesk.Revit.Exceptions ArgumentOutOfRangeException	When setting this property: startTangent is not length 1.0.
Autodesk.Revit.Exceptions InapplicableDataException	The start tangent value is not set.