Synopsis

PDX_MSGT gdx_EvalNurbSurfDerivs(long option, T_GDX_NURB_SURF *gdx_nurbs_surf, int max_u_deriv, int max_v_deriv, double uval, double vval, double derivs[][GDX_MAX_DEG+1][3])

Purpose

Evaluate derivatives on a GDX NURB Surface.

Description

For a given U and V parameter value, evaluates the derivatives on a GDX NURB Surface.

Input

option

GDX_UNNORM

Unnormalize the parameter value

GDX_FROMLEFT

Evaluate derivatives from the left

GDX_FROMLOW

Find the knot span from the low direction

gdx_nurbs_surf

The GDX NURB Surface data structure.

max_u_deriv

The maximium U deriviative desired

max_v_deriv

The maximium V deriviative desired

uval

The U parameter value

vval

The V parameter value

Output

derivs

The 3D mixed deriviatives

Return

      GDX_NOERR
      GDX_PARMOUTOFRANGE
      .fi