# Synopsis

void mth_GetPntPlaneMatrix(long iopt, MTH_3DPNT p1, MTH_3DPNT p2, MTH_3DPNT p3, double *r)

# Purpose

Get a 3X3 rotation matrix for a three point plane

# Description

Determines the 3X3 rotation matrix for a plane defined by three points

# Input

## iopt

Specification option .br 0 = use exact points for matrix .br 1 = check for identity planes

## p1

First plane point

## p2

Second plane point

## p3

Third plane point

# Output

## r

3X3 rotation matrix