Thats correct.  [] signifies 1/100 mil and () signifies 1 mil.  Historically
PCB used 1 mil as the fundamental unit of length.  Everything is stored internally
as integers, so 1 mil was the resolution.  Early last year harry dropped the
fundamental unit to 1/100 mil to allow finer resolutions required by todays
packages.  Much of the library is still using the 1 mil units, and PCB will
still parse those.  So its not uncommon (in fact its typical) to see that
the output of something like gsch2pcb produces elements with () and units
in mils and afterwards PCB will save in hi-res format using [] and 1/100 mils.
There are a few footprint families which use the hi-res format.  For example,
try out a QFN package from the ~geda library.  In the gsch2pcb output you'll
see [] and 1/100 mil.

This is part of the source of confusion in the documentation.  There is quite
a bit of work involved with updating all of the footprints to the new format
and in fact different footprints in the library use differing old formats.
PCB still parses them all.  It makes clearly documenting things a bit of
a pain, but I'm still working on trying to fix footprints which are outright
broken so bringing old footprints to a new file format is low on my list.

-Dan

On Sun, Oct 31, 2004 at 07:09:50AM -0800, Stephen Meier wrote:
> opps that should be
> 
> macro [parm1 parm2 parm3]
> 
> Stephen Meier wrote:
> 
> >Yes that is my understanding.
> >
> >If you use [macro parm1 parm2 parm3] then parms are expected to be in 
> >0.00001 inch resolution (1/100th of a mil)
> >
> >If you use (macro parm1 parm2 parm3) then the parms are expected to be 
> >in 0.001 inch resolution  (1 mil)
> >
> >
> >Stuart Brorson wrote:
> >
> >>Umm, I guess that the use of [] instead of () signals the change in 
> >>units,
> >>right?  Or how does one know which units are in play?
> >>
> >>Stuart
> >>
> >> 
> >>
> >
> >
> 
> 

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