# LineLineIntersection

Calculates the intersection of two non-parallel lines. Note, the
two lines do not have to intersect for an intersection to be found.

The default operation of this function assumes that the two lines are
co-planar. Thus, the return value is the intersection point of the
two lines.

But, two lines in three dimensions generally do not intersect at a point.
They may be parallel (no intersections) or they may be coincident (infinite
intersections). But, most often only their projection onto a plane intersects.
When they do not exactly intersect at a point they can be connected by
a line segment, the shortest line segment is unique and is often considered
to be their intersection in 3-D.

### Syntax

Rhino.LineLineIntersection (arrLineA, arrLineB [, blnPlanar])

### Parameters

arrLineA |
Required. Array. Two 3-D points
identifying the starting and ending points of the first line. |

arrLineB |
Required. Array. Two 3-D points
identifying the starting and ending points of the second line. |

blnPlanar |
Optional. Boolean. Assume that
the two lines are co-planar. The default value is True. |

### Returns

Array |
If *blnPlanar*
is omitted or True, then a single 3-D intersection point if successful. |

Array |
If *blnPlanar*
is False, then an array containing a point on the first line and
a point on the second line if successful. |

Null |
If not successful, or on error. |

### Example

Dim arrLineA, arrLineB, arrPoint

arrLineA = Array(Array(1,1,0),
Array(5,0,0))

arrLineB = Array(Array(1,3,0),
Array(5,5,0))

arrPoint = Rhino.LineLineIntersection(arrLineA,
arrLineB)

If IsArray(arrPoint) Then

Rhino.AddPoint arrPoint

End If

### Also See

LineArcIntersection

LineBoxIntersection

LineCircleIntersection

LineCylinderIntersection

LinePlaneIntersection

LineSphereIntersection