The POLYGON command is used to draw polygon areas. Polygons in the layers Top, Bottom, and Route2..15 are treated as signals. Polygons in the layers t/b/vRestrict are protected areas for the Autorouter.
Note
You should avoid using very small values for the width of a
polygon, because this can cause extremely large amounts of data when
processing a drawing with the CAM Processor.
The polygon width should always be larger than the hardware
resolution of the output device. For example when using a Gerber photoplotter
with a typical resolution of 1 mil, the polygon width should
not be smaller than, say, 6 mil. Typically you should keep the polygon
width in the same range as your other wires.
If you want give the polygon a name that starts with a digit (as in 0V),
you must enclose the name in single quotes to distinguish it from a width value.
Outlines or Real Mode
Polygons belonging to a signal can be displayed in two different modes:
1. Outlines | only the outlines as defined by the user are displayed. |
2. Real mode | all of the areas are visible as calculated by the program. |
The board file contains only the "outlines".
The default display mode is "outlines" as the calculation is a time consuming operation.
When a drawing is generated with the CAM Processor all polygons are calculated.
Ctrl-Break terminates the calculation of the polygons. Already calculated polygons are shown in "real mode", all others are shown in "outline mode".
The RATSNEST command starts the calculation of the polygons (this can be turned off with SET POLYGON_RATSNEST OFF;).
The RIPUP command changes the display mode of a polygon to "outline".
CHANGE operations re-calculate a polygon if it was shown in "real mode" before.
Other commands and Polygons
Polygons are selected at their edges (like wires).
SPLIT: Inserts a new polygon edge.
DELETE: Deletes a polygon corner (if only three corners are left the whole polygon is deleted).
CHANGE LAYER: Changes the layer of the whole polygon.
CHANGE WIDTH: Changes the parameter width of the whole polygon.
MOVE: Moves a polygon edge or corner (like wire segments).
COPY: Copies the whole polygon.
NAME: If the polygon is located in a signal layer the name of the signal is changed.
Parameters
Width: Line width of the polygon edges. Also used for filling.
Layer: Polygons can be drawn into any layer. Polygons in signal layers belong to a signal and keep the distance, defined with the parameter Isolate, from other signals. Objects in the tRestrict layer are substracted from polygons in the Top layer (the same applies to bRestrict/Bottom). This allows you, for instance, to generate "negative" text on a ground area.
Pour: Fill mode (Solid [default] or Hatch).
Thermals: Defines how pads and smds are connected (On = thermals are generated [default], Off = no thermals).
Spacing: Distance between fill lines when Pour = Hatch (default: 50 Mil).
Isolate: Distance between polygon areas and other signals (default: 14 Mil).
Orphans: As a polygon automatically keeps a certain distance to other signals it can happen that the polygon is separated into a number of smaller polygons. If such a polygon has no electrical connection to a pad, via-hole, or smd of the same signal, the user might want it to disappear. With the parameter Orphans = Off [default] these isolated zones will disappear. With Orphans = On they will remain.
Under certain circumstances, especially with Orphans = Off, a polygon can disappear completely.
Thermal Dimensions
The width of the conducting path in the thermal symbol is calculated as follows:
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