Справочник Пользователя для National Instruments Ultiboard

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Use smaller Keep-out or Keep-in areas. Often, a PCB with Keep-in 
areas can be designed with an equivalent set of Keep-out areas, or 
vice-versa. Whenever possible, choose a design strategy that 
minimizes the total area of the board covered by these Keep-in or 
Keep-out areas since each area radically decreases the autoplacement 
algorithms’ effectiveness. 

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The autoplacement algorithms have been carefully 

tuned to optimize the routability of the final layout, rather than trying 
to pack all the parts into the smallest possible area. If the autoplacer 
places all but one or two parts, it may be faster to simply place them on 
the board by hand—using Ultiboard’s part shoving facility (not 
available in all versions) to ensure that parts do not overlap—than to 
spend time trying to tune the autoplacement parameters to achieve 
complete placement.

The following sections describe the autorouting functions in Ultiboard. 

Ultiboard contains four fundamental trace-routing functions:

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router preprocessing

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initial routing

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rip-up and retry passes

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optimization.

Ultiboard uses combinations of these functions to route a board. They are 
described in the 

 

section. Information on how to use these functions can be found in the 

 section.