# Synopsis

PDX_MSGT mth_DistanceBetween3DLines(long option, double para_tol, double *pt1, double *tan1, double *pt2, double *tan2, double *alf1, double *alf2, double *dist)

# Purpose

Solves for two straight lines in 3D space (least squares).

# Description

This routine solves the equations of two straight lines in 3D spaces. The lines must be in point/vector form. The lines may or may not intersect. If they do not intersect, the solution represents the minimum distance between the two lines.

# Input

## option

Output options (Not used)

## para_tol

The parallel lines test tolerance.

## pt1

The initial point on the first line.

## tan1

The tangent vector of the first line.

## pt2

The initial point on the second line.

## tan2

The tangent vector of the second line.

# Output

## alf1

Parametric solution to equation 1

## alf2

Parametric solution to equation 2

## dist

The distance between the two lines.

# Return

          MTH_NOERR
          MTH_PARALLELLINES (alf1 = 0.0 and alf2 = proj. of alf1 point to line 2)
          .fi