# Synopsis

int mth_PointIn3PtPlane(MTH_3DPNT pt1, MTH_3DPNT pt2, MTH_3DPNT pt3, MTH_3DPNT pt, double toler)

# Purpose

Check if point is in plane defined by three other points.

# Description

This routine determines if a point is contained in the plane defined by three other points.

# Input

## pt1

First of 3 points defining plane.

## pt2

Second of 3 points defining plane.

## pt3

Third of 3 points defining plane.

## pt

Point to be determined if it lies in plane of other three.

## toler

Tolerance. Measures length of a 3D vector.

# Return

          -1 : Three points do not define a plane.
           0 : pt is not in the plane defined by the 3 points.
           1 : pt is in the plane defined by the 3 points.
          .fi