# Synopsis

PDX_MSGT gdx_ExtractSubCurve(long option, int model, T_GDX_NURB_CURVE *curve, double u1, double u2, double clo_tol, void *gdx_cur)

# Purpose

Extract a subcurve from a GDX NURB Curve.

# Description

Given start and end parameters, u1 and u2, extract that section of the curve between u1 and u2 (as a GDX NURB Curve). Let umin,umax be the first and last knot values respectively. Then the following must hold: umin <= u1 < u2 <= umax, and either u1 != umin or u2 != umax and no more than oderful internal knot multiplicities. The degree and rationality of the subcurve do not change.

# Input

## option

### GDX_COMMIT

Entity creation option. Commit GDX entity to the datbase. The default is do not commit.

## model

The GDX model for entity creation.

## curve

Pointer to the GDX NURB Curve from which the subcurve is to be extracted.

## u1

Start parameter defining the subcurve.

## u2

End parameter defining the subcurve.

## clo_tol

Tolerance for checking closure of curves.

# Output

## gdx_cur

Pointer to the created GDX NURB Curve.

# Tolerances

          KNOT_TOL
          COPLANAR_TOL
          .fi

# Return

          GDX_NOERR
          GDX_BADSUBPARMS
          Low level error return
          .fi