## SYNTAX

void gleLathe (int ncp, gleDouble contour[][2], gleDouble cont_normal[][2], gleDouble up[3], gleDouble startRadius, /* spiral starts in x-y plane */ gleDouble drdTheta, /* change in radius per revolution */ gleDouble startZ, /* starting z value */ gleDouble dzdTheta, /* change in Z per revolution */ gleDouble startXform[2][3], /* starting contour affine xform */ gleDouble dXformdTheta[2][3], /* tangent change xform per revoln */ gleDouble startTheta, /* start angle in x-y plane */ gleDouble sweepTheta); /* degrees to spiral around */

## ARGUMENTS

*ncp*- number of contour points
*contour*- 2D contour
*cont_normal*- 2D contour normals
*up*- up vector for contour
*startRadius*- spiral starts in x-y plane
*drdTheta*- change in radius per revolution
*startZ*- starting z value
*dzdTheta*- change in Z per revolution
*startXform*- starting contour affine transformation
*dXformdTheta*- tangent change xform per revolution
*startTheta*- start angle in x-y plane
*sweepTheta*- degrees to spiral around

## DESCRIPTION

Sweep an arbitrary contour along a helical path. The sweep will be performed as a shear along the z-axis, so that the orientation of the contour is displaced, rather than translated, as the contour is swept.

The axis of the helix lies along the modeling coordinate z-axis.

An affine transform can be applied as the contour is swept. For most ordinary usage, the affines should be given as NULL.