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 (17.0.1090.0)

Syntax

C#
`public Transform ComputeDerivatives( UV point )`

Visual Basic
`Public Function ComputeDerivatives ( _ point As UV _ ) As Transform`

Visual C++
`public: Transform^ ComputeDerivatives( UV^ point )`

point: Type: Autodesk.Revit.DB UV
The parameters to be evaluated, in natural parameterization of the face.

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) .

None of the vectors are normalized.