# gluPwlCurve.3G man page

gluPwlCurve — describe a piecewise linear NURBS trimming curve

## C Specification

**void gluPwlCurve(GLUnurbs*** *nurb***, GLint** *count***, GLfloat*** *data***, GLint** *stride***, GLenum** *type***);**

## Parameters

*nurb*Specifies the NURBS object (created with

**gluNewNurbsRenderer**()).*count*Specifies the number of points on the curve.

*data*Specifies an array containing the curve points.

*stride*Specifies the offset (a number of single-precision floating-point values) between points on the curve.

*type*Specifies the type of curve. Must be either

**GLU_MAP1_TRIM_2**or**GLU_MAP1_TRIM_3**.

## Description

**gluPwlCurve** describes a piecewise linear trimming curve for a NURBS surface. A piecewise linear curve consists of a list of coordinates of points in the parameter space for the NURBS surface to be trimmed. These points are connected with line segments to form a curve. If the curve is an approximation to a curve that is not piecewise linear, the points should be close enough in parameter space that the resulting path appears curved at the resolution used in the application.

If *type* is **GLU_MAP1_TRIM_2**, then it describes a curve in two-dimensional (*u* and *v*) parameter space. If it is **GLU_MAP1_TRIM_3**, then it describes a curve in two-dimensional homogeneous (*u*, *v*, and *w*) parameter space. See the **gluBeginTrim**() reference page for more information about trimming curves.

## Notes

To describe a trim curve that closely follows the contours of a NURBS surface, call **gluNurbsCurve**().

## See Also

**gluBeginCurve**(), **gluBeginTrim**(), **gluNewNurbsRenderer**(), **gluNurbsCurve**()

## Copyright

Copyright © 1991-2006 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see http://oss.sgi.com/projects/FreeB/.

## Authors

**opengl.org**