# Synopsis

PDX_MSGT gdx_EvalNurbSurfPnt(long option, T_GDX_NURB_SURF *gdx_ns, double uval, double vval, MTH_3DPNT point)

# Purpose

Evaluate a point on a NURBS surface.

# Description

Given the GDX NURB Surface and a U and V parameter value evaluates a point on the surface at the given UV parameter value.

# Input

## option

### GDX_UNNORM

Unnormalize the parameter value

### GDX_FROMLEFT

Evaluate from the left

### GDX_FROMLOW

Find the knot span from the low direction

## gdx_ns

The GDX NURB surface data structure

## uval

U surface parmeter value

## vval

V surface parmeter value

# Output

## point

Resulting point

# Return

          GDX_NOERR
          Low level error return.
          .fi