Introduction
Set Teardrop Attribute
is a cleanup action intended to identify teardrop features in a layer that are not marked with the
.tear_drop
attribute.
Teardrop features can be a line, an arc, a pad or a surface.
A teardrop is a feature or set of features that is added to a connection between a pad and a trace entering the pad.
The teardrop strengthens the connection between the pad and the incoming trace.
Teardrop Examples
Incoming Trace
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A normal trace, line, or arc which connects the pad to the other feature.
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Teardrop
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Feature which connects a pad and a line entering the pad. A feature can be a line, an arc, a pad, or a surface.
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Swallow shape teardrop
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Skeleton of the line teardrop is shaped like a swallow (a type of bird).
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Oval shape teardrop
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Skeleton of the teardrop is shaped like an oval.
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Surface shape teardrop
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Skeleton of the teardrop is shaped like an oval.
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How the Algorithm Identifies Teardrops
For line or arc teardrops (center_trance type)
The algorithm locates where the trace
enters the pad, then identifies the features that connect to the pad at
the point where the trace enters the pad.
For pad/surface teardrops
The algorithm determines whether the
candidate teardrop pad or surface is closer to the pad being enlarged,
then determines if the surface width is larger than the trace width. If
the surface width is larger than the width of the trace, than the
surface is a teardrop.