The layer control panel, located below the panner control, is used to turn on and off the display of layer groups and to select the active drawing layer. If a layer hasn't been named, the label "(unknown)" is used as the default. If this happens, it probably means the application resources are not installed properly.
The upper buttons are used to switch layers on and off. Click
<Btn1> on one or more of them. Each click toggles the setting.
If you turn off the currently active layer, another one that is visible
will become active. If there are no others visible, you will not be
able to turn off the active layer.
When the layers are grouped, clicking on these buttons will toggle
the visibility of all layers in the same group. This is a good idea because
layers in the same group reside on the same physical layer of
the actual board. Notice that this example has 2 groups each having
3 layers, plus two other layers named unused
.
Use the Edit layer groups
option in the Settings
menu to
change the layer groupings. Note that changing the groupings can
radically alter the connectivity on the board.
Grouping layers is only useful for helping you to color-code
signals in your layout. Note that grouping layers actually reduces the number
of different physical layers available for your board, so to make an eight
layer board, you cannot group any layers.
The far side button turns on and off the visibility of elements (including SMD pads) on the opposite (to the side you're viewing) board side, as well as silk screening on that side. It does not hide the x-ray view of the other copper layers, these must be turned off separately if desired. Use the tab key to view the entire board from the other side. To see a view of what the back side of the board will actually look like, make the solder layer the active layer then press tab until the status line says "solder" on the right, then turn off the visibility of all layers except solder, pins/pads, vias, and silk. Now turn them all back on.
The lowest button, named active, is used to change the active
drawing layer. Pressing <Btn1> on it pops up a menu to select which
layer should be active.
Each entry is labeled with the layer's name and drawn in its color.
The active layer is automatically made visible. The active layer is
always drawn on top of the other layers, so the ordering of layers
on the screen does not generally reflect the ordering of the manufactured
board. Only the solder, component, silkscreen, and solder-mask layers
are always drawn in their physical order. Bringing the active layer
to the top makes it easier to select and change objects on the active layer.
Try changing the active layer's name to ABC by selecting
edit name of active layer
from the Edit
menu.
Changing the active layer can also be done by pressing keys
1..MAX_LAYER.
Turn off the visibility of the component layer. Now make the component layer the active layer. Notice that it automatically became visible. Try setting a few other layers as the active layer. You should also experiment with turning on and off each of the layers to see what happens.
The netlist layer is a special layer for adding connections to the netlist by drawing rat lines. This is not the recommended way to add to the netlist, but occasionally may be convenient. To learn how to use the netlist layer see Net Objects.