# Synopsis

PDX_MSGT gdx_SurfaceGetRevolveParms(long option, MDA_PTR gdx_surf_ptr, PDX_BOOL *rev_flag, double *span_angle, MTH_3DPNT center_pnt, MTH_3DVEC vec_axis, PDX_BOOL *v_revolve, PDX_BOOL *planar_curve, MTH_3DVEC vec_seam)

# Purpose

Find the parameters of a revolving surface

# Description

The revolve parameters of a GDX surface will be found if the surface is a revolve one. The surface can be any GDX surface.

If not a revolve surface, the function returns GDX_NOERR and rev_flag = PDX_FALSE.

Some parameters might not be available if the generatrix curve is not on a plane that passes through the revolving axis

# Input

## option

Options (not used)

## gdx_surf_ptr

The valid GDX surface database pointer

# Output

## rev_flag

Flag indicating whether or not the surface is a revolution (could not compute the defining data)

## span_angle

The span angle of the surface, i.e. the difference of the start angle and the end angle

## 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.

## planar_curve

The flag indicating if the generatrix curve is on a plane that passes through the revolving axis

## vec_seam

The vector that is perpendicular to the revolving axis as well as on the plane that goes through the seam of the surface and the revolving axis if the generatrix curve is on a plane that goes through the revolving axis

# Return

          GDX_NOERR
          Low level error return
          .fi