# Synopsis

PDX_MSGT gdx_RevSurfAngleParmPoint(long option, double parm, MDA_PTR gdx_surf_ptr, MTH_3DPNT center_pnt, MTH_3DVEC vec_axis, PDX_BOOL v_revolve, double *angle)

# Purpose

Find the angle of a parm point on a revolving surface

# Description

The angle of a point in parameter space on a revolving surface is computed. The angle is measured about the revolving axis from the seam of the surface with right hand rule.

The surface must be of revolution and the parameter must not be normalized.

# Input

## option

Options (not used)

## parm

The parameter in revolving direction

## gdx_surf_ptr

The valid GDX surface database pointer

## center_pnt

A point on the revolve axis

## vec_axis

The vector of the revolve axis

## v_revolve

Flag indicating if the revolve direction is the surface's v-direction.

# Output

## angle

The angle of a point in parameter space on a revolving surface

# Return

          GDX_NOERR
          Low level error return
          .fi