M

Face.ComputeDerivatives

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.

public Transform ComputeDerivatives(
	UV point
)

Public Function ComputeDerivatives ( _
	point As UV _
) As Transform

public:
Transform^ ComputeDerivatives(
	UV^ point
)

Autodesk.Revit.DB.UV

point

The parameters to be evaluated, in natural parameterization of the face.

Return Value Transform A transformation containing tangent vectors and a normal vector.