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.
If the curve or @radius parameter is given, an arc can be drawn as part of the polygon definition (see the detailed description in the WIRE command).
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 to 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.
The parameters Isolate and Rank only have a meaning for polygons in layers Top...Bottom.
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.
Clicking the STOP button 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.
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 in the design rules and net classes 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).
Rank: Defines how polygons are subtracted from each other. Polygons with
a lower 'rank' appear "first" and thus get subtracted from polygons with a higher 'rank'.
Valid ranks are 1..6 for signal polygons and 0 or 7 for polygons in packages. Polygons with the same rank are checked against each other by the Design Rule Check. The rank parameter only has a meaning for polygons in signal layers (1..16) and will be ignored for polygons in other layers. The default is 1 for signal polygons and 7 for package polygons.
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 or objects in the Dimension layer (default: 0). If a particular polygon is given an Isolate value that exceeds that from the design rules and net classes, the larger value will be taken. See also Design Rules under Distance and Supply, respectively.
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 any other (non-polygon) object of its 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. If none of the polygon parts has any such connection, all polygon parts will remain, independent of the setting of the Orphans parameter.
Under certain circumstances, especially with Orphans = Off, a polygon can disappear completely. In that case the polygon's original outlines will be displayed on the screen, to make it possible to delete or otherwise modify it. When going to the printer or CAM Processor these outlines will not be drawn in order to avoid short circuits.
The width of the conducting path in the thermal symbol is calculated as follows:
The special signal name _OUTLINES_ gives a polygon certain properties that are used to generate outlines data (for example for milling prototype boards). This name should not be used otherwise.
|Index||Copyright © 2005 CadSoft Computer GmbH|