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	Mon, 14 Sep 2015 23:42:20 -0700 (PDT)
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> > These issues should probably only matter if current number is used
> > to calculate next number instead of using an absolute value. For
> > example if an object is rotated with angular transformation of
> > current coordinates over and over again.
> 
> The issues matter because of usability.
> 
> Is there any other solution than double-entry in this case, to have
> both a closed internal representation which can be rasterized at
> arbitrary resolutions, plotted as gerber/ps *and* a closed system
> for user input<->output ?
> 
> As a bonus, double-entry would allow internal consistency checks to
> some degree.

A closed system there files could be transferred back and forth between for example pcb <--> gerber without rounding errors would indeed be very nice.

For rotation if you rotate a component already rotated with 45 degrees with 45 more degrees original figure is rotated with 90 degrees. If however the 45 degree rotated figure is rotated once more with 45 degree errors add up. It should be a similar problem with float if it is moved 1/10 of a unit without snapping to a grid.

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