Namespace: Autodesk.Revit.DB Class: Face

Face.ComputeDerivatives

Method

Description:
Returns the first partial derivatives of the underlying surface at the specified point.

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.

Syntax

public Transform ComputeDerivatives(
	UV point
)

Public Function ComputeDerivatives ( 
	point As UV
) As Transform

public:
Transform^ ComputeDerivatives(
	UV^ point
)

member ComputeDerivatives : 
        point : UV -> Transform

Parameters

Parameter	Type	Description
point	UV	The parameters to be evaluated, in natural parameterization of the face.

Return Value

Type	Description
Transform	A transformation containing tangent vectors and a normal vector.