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ComputeDerivatives Method

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
)

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) .
None of the vectors are normalized.

See Also