Returns the first partial derivatives of the underlying surface at the specified point.
Namespace:
Autodesk.Revit.DB
Assembly:
RevitAPI
(in RevitAPI.dll) Version: 17.0.0.0 (17.0.484.0)
Syntax
C# 


Visual Basic 


Visual C++ 


Parameters
 point

Type:
Autodesk.Revit.DB
UV
The parameters to be evaluated, in natural parameterization of the face.
Return Value
A transformation containing tangent vectors and a normal vector.Remarks
The following is the meaning of the transformation members:
 Origin is the point on the face (equivalent to Evaluate(UV) );
 BasisX is the tangent vector along the U coordinate (partial derivative with respect to U).
 BasisY is the tangent vector along the V coordinate (partial derivative with respect to V).
 BasisZ is the underlying surface's normal vector. This is not necessarily aligned with the normal vector pointing out of a solid that contains the face, to get that value use ComputeNormal(UV) .