Re: gEDA-user: pcb crooked traces

[gedau@xxxxxxxxxxxxx]

On Mon, Oct 11, 2010 at 01:57:48PM -0700, Andrew Poelstra wrote:
> On Mon, Oct 11, 2010 at 10:19:39PM +0200, Stefan Salewski wrote:
> > On Mon, 2010-10-11 at 11:26 -0700, Andrew Poelstra wrote:
> > 
> > > I'm just throwing ideas into the air. What do you guys think?
> > > 
> > 
> > Andrew, I am not sure if you know that there was already a transition
> > from mil to 0.01 mil long time ago -- maybe that is useful information,
> > but that was before I started PCB, so I have no detailed information.
> >
> 
> Thanks, I'll look through the mailing list logs to see if there
> were any oddities I should be aware of.
>  
> > What is your conclusion -- if we use 32 bit integer and nm base unit,
> > will we have maximun board size of 2m or 4m. That was not fully clear in
> > our discussion two years ago -- it does not really matter, but may be
> > good to know and to proof our understanding.
> > 
> 
> For the people who need to make giant PCBs on 32-bit systems, we should
> introduce a scale factor to the file format (254 by default, to maintain
> compatibility with existing .01mil files).
> 
> Maybe the scale factor should be a float, so that boards can be made
> with sub-nanometer precision?
> 
> In any case, I don't think the scale factor should be accessible from
> the GUI, just there for edge cases and people who like to hand-edit their
> pcb files. It could cause problems importing footprints whose grid is
> smaller than the base unit.
> 

Wouldn't a float scale slow things down? Anyway if you need to modify a 
lot of source files for this already, what about using a typedef 
SIZE_UNIT instead of a hardcoded int or long int or long long int? Then the 
typedef should default to long, which is good up to at least 2m, and if 
someone really needs to make a bigger board on a 32 bit system, he can 
modify the typedef to long long.

I think the only barrier is that you need to decide whether you use int 
or float, as some calculations would be broken if they were designed for 
ints and someone changed the typedef to float. But because those 
claculations you alrady need to decide on that, so no difference.

Regards,

Tibor


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