Auxiliary Polygon

The auxiliary polygon is an object having no acoustical relevance. It can be used to generate open or closed polygon lines to enhance the graphical representation.

Closed Polygon

Auxiliary polygons can either be open or closed. Check or uncheck the option „Closed Polygon“ as required.

Note

The 2D-length displayed via button „Geometry“ of a closed polygon is twice the length of the polygon not being closed.

Use Global Properties

The appearance of the auxiliary polygons can either be changed globally (via Options|Appearance menu) or individually via its edit dialog. Each polygon can have a different color, line width or line type. To enable this, first deactivate this option.

Arrow

Various types of arrow heads are selectable from the list. The arrow head will be attached to the end point of the auxiliary polygon. The arrow’s size is specified on dialog Options|Appearance, object type „Aux. Polygon“ (arrow size <> 0 in mm or m).

Use the command Modify Order of Points to invert the order of points (see Modify Order of Points in the manual „Introduction to CadnaA“).

Auxiliary Polygons and DTM

Auxiliary polygons are not fitted to the digital terrain model. When this is required convert them into e.g. line sources. Switch to the 3D-View on Options|3D-View menu. CadnaA determines the heights of polygon points. Afterwards convert them back again to auxiliary polygons.

Button Protocol

see Protocol and Receiver.

Color Attributes for Auxiliary Polygons

With the command Modify Objects (or when importing via ODBC interface colors can be allocated to auxiliary polygons.

The meaning of the color attribute ?_COLOR of auxiliary polygons is:

L_COLOR defines the color of the line andF_COLOR defines the color of the filling.

?_COLORR is r, the red component (0..255)?_COLORG is g, the green component (0..255)?_COLORB is b, the blue component (0..255)

?_COLOR and ?_COLORX is the sum r+256*g+256*256*b,

where

?_COLOR is a decimal value and

?_COLORX a hexadecimal.

Closed Auxiliary Polygons in 3D

Using „FollowDGM=1“ as string variable in the memo field of the auxiliary polygon enables the area covered by the closed auxiliary polygon to follow the terrain.