# Intersection perpendicular through 3rd point#

Intersection perpendicular through 3rd Point
 Command SOF_CM_CONSTRUCTIONMODEPOINT Tooltip Locates a point in the intersection of a line and the perpendicular. Sidebar Cross Section Editor
Locates a point in the intersection of a line and the perpendicular.

The distances between the involved points can’t be set explicitly by a variable or a explicitly given fix distance. The distances depends only on the existing geometry.

## Input#

At first a point (dependent point), whose coordinates are parametrically / dependent, has to be defined (point A in the diagram).

Then a cross section point (reference point, point B in the diagram) can be input in order to define the first point of a straight line which is to be be used to form the reference line BC.

Then a point (reference point, point C in the diagram) has to be defined for the second reference point of the straight line BC.

At last, the cross section point (reference point, point D in the diagram) is necessary for the definition of the location of the perpendicular on the reference line BC.

If a point which was not yet created as a “cross section point” is to be used for a reference point, then a geometry point can be generated at this position.

## Symbolism#

The double arrow symbolises the straight line BC and the single arrow with the solid line the perpendicular to the straight line. The arrow with dashed line symbolises the new location of point A.

Reference points are represented by a blue triangle and dependent points by a yellow circle.

## Editing#

Dependent points are marked by a circle with a diagonal cross within. By left clicking on this symbol, the entire reference object is shown. Then it can be edited according to the following procedure:

The reference points and the dependent point can be moved by left-clicking on the object and by pulling of the point to another (permissible) cross section point position.

If the mouse cursor shows to the grip point of the dependent point A, a menu is displayed where the reference can be switched between the intersection with the vertical, the intersection with the horizontal and the intersection with the perpendicular.

## Deleting#

A reference can be selected by left-clicking on the reference symbol and then it can be deleted by using the delete key or with the AutoCAD delete command.