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From PADS Layout Concepts Guide: Layer Modes
PADS Layout supports two layer modes: default layer mode (30 layers) and increased layer mode
(up to 250 layers). In default layer mode, the 30 layer maximum can consist of up to a maximum
of 30 electrical layers or a combination of electrical and nonelectrical layers. In increased layer
mode, the maximum number of electrical layers is 64 and the maximum number of nonelectrical
layers is 186, for a total of 250 layers. The total number of layers includes associated layers such as
mask, silk screen, drill drawing, and assembly layers.
You change from default layer mode to increased layer mode by clicking the Max Layers button in
the Layers Setup dialog box. Changing from default layer mode to increased layer mode increases
all nonelectrical layer numbers by 100.
Restriction: Once you change the design to increased layer mode, you cannot return to default
layer mode.
In default layer mode, layer number 20 is used for placement outlines. In increased layer mode,
layer 120 is used for placement outlines. Layer 25 in default layer mode, or 125 in increased layer
mode, is used for oversizing thermals and antipads.
In default layer mode, you can only import, add, or load other default layer mode items, such as
files or library items, to your design. You cannot load increased layer mode objects into the default
layer mode design. In increased layer mode, you can load both default and increased layer mode
objects into your design.
Restriction: You cannot export a design with more than 30 electrical layers to a PADS Layout
PADS-format ASCII file prior to version 4.0.
You don't have to convert existing default layer mode libraries, reuse files, or archived designs to
increased layer mode. You can use existing library decals, drawings, and reuses that are saved in
default layer mode for both default and increased layer mode designs. You can cut from a design in
default layer mode and paste into a design in increased layer mode. If you make sure that you have
consistent layer definition in libraries, reuses, and designs, no problems with layer matching will
occur.
Either default or increased layer mode is specified in each design or design fragment such as .pcb,
.asc, .stp, .dxf, .reu, and high speed .edp files, library decals and drawing items, copy/paste buffer,
and external CAM documents. | 
发表于 2008-5-26 08:55:00
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