RhinoCommon API
CurveGetLocalTangentPoint Method (Point3d, Double, Double) | 
            Search for a location on the curve, near seedParmameter, that is tangent to a test point.
            
Namespace: Rhino.Geometry
Assembly: RhinoCommon (in RhinoCommon.dll)
public bool GetLocalTangentPoint( Point3d testPoint, double seedParmameter, out double curveParameter )
Public Function GetLocalTangentPoint ( testPoint As Point3d, seedParmameter As Double, <OutAttribute> ByRef curveParameter As Double ) As Boolean
Parameters
- testPoint
 - Type: Rhino.GeometryPoint3d
The test point. - seedParmameter
 - Type: SystemDouble
A "seed" parameter on the curve. - curveParameter
 - Type: SystemDouble
The parameter value at the tangent point 
Return Value
Type: BooleanTrue if a solution is found, false otherwise.