kicad-developers team mailing list archive

[R P Herrold <herrold@xxxxxxxxxxxx>]

On Wed, 5 Aug 2015, Wayne Stambaugh wrote:

> >>> to that? Some (particularly older and non-Asian) board houses still 
> >>> expect those... Is there any reason they were removed

so, an articulated use case for the inch output

>> AFAIK there would be no technical reason to not do inch 
>> plotting...

> If we use a 6 digits mantissa and mm in Gerber, there is no 
> rounding issue.

or perhaps it just crops up more rarely?  Absent edge path 
interference auditting, it would seem so

I guess I don't see how using any numbering system in the 
output side does not carry the prospect for potential overlap.  
I _think_ you are saying 'using the same precision' for 
internal representation rather than transitions 'back and 
forth' and so having accumulating 'roundoff indeterminancy / 
error' terms in play helps avoid inadvertently producing:
	 Self intersecting polygons

at gerber output time, minimizes this occurring?

> > We already have a bug report about self intersecting polygons in Gerber
> > files from Kicad.

This seems like 'papering over' an issue, rather than 
detecting closure (and, so, an inadvertent failure to close), 
and 'intrusion' by adjacent entities (a convex hull / boundry 
problem)

-- Russ herrold