pcb-rnd knowledge pool
term_layers by Tibor 'Igor2' Palinkas on 2017-01-05
Tags: spec, layer, group, terminology
Abstract: Specify the terminology of layers.
The exact specification of the layer model can be found in the user manual. The table below is an extract of the most commonly used terms.
|layer||logical layer, canvas; may be positive (==additive) or negative (==subtractive); negative not supported on copper|
|layer group||physical layer of the board; a group hosts an ordered list of layers|
|auto layer||side effects (automatic drawings) from elements, subcircuits, etc. will use this layer|
|layer group type||material/purpose of the layer group (e.g. copper, mask, silk, substrate)|
|substrate||layer group type; does not host layers; any insultion layer|
|top layer group||at the natural/default orientation of the board, the given layer group of the given type is an outer group and is on top or bottom; e.g. top silk group, bottom copper group|
|bottom layer group|
|internal layer group||any layer group that is in between top and bottom layer groups|
|global layer group||the group affects all physical layers, e.g. the outline layer that cuts through the whole board|
|layer stack||the ordered list, from top to bottom, of layer groups|
|layer object||an object (e.g. line, polygon) that is on a specific layer|
|global object||an object (e.g. a padstack or a subcircuit) that is on the board, but is not limited to one layer or one layer group|
|cross section view||GUI feature that shows a cross section of the board, typically to describe the layer stack|
Note: we used to use terminology "component" and "solder" side. We stopped using those terms because they do not make sense on modern SMD or even mixed boards where both sides may host SMD and/or through-hole components.