kicad-developers team mailing list archive

[Cirilo Bernardo <cirilo_bernardo@xxxxxxxxx>]

----- Original Message -----

> From: jp charras <jp.charras@xxxxxxxxxx>
> To: kicad-developers@xxxxxxxxxxxxxxxxxxx
> Cc: 
> Sent: Thursday, December 19, 2013 6:27 AM
> Subject: Re: [Kicad-developers] bugs 1261583 and 1236583
> 
> Le 18/12/2013 19:36, Wayne Stambaugh a écrit :
>>  On 12/18/2013 1:29 PM, jp charras wrote:
>>>  Le 18/12/2013 06:02, Cirilo Bernardo a écrit :
>>>>  These bugs are identical and concern the 3D viewer (rectangular
>>>>  outline used because adjacent segments fail the exact endpoint
>>>>  test).
>>>> 
>>>>  The line causing this is in specctra_export.cpp, line 1011:
>>>> 
>>>>  prox = Mils2iu( 0 );
>>>> 
>>>> 
>>>>  I did not submit a patch because I believe some discussion is
>>>>  necessary about the limit imposed for the closeness of points and 
> the
>>>>  routine (fillBOUNDARY) is also used by the specctra exporter.  In 
> bug
>>>>  1236583 the user has points which differ by 500nm.  In bug 1261583
>>>>  the difference in the DXF file is less than 10nm.
>>>> 
>>>>  Is it possible to change the limit without adversely affecting the
>>>>  specctra export, and if so, what limit would people consider
>>>>  reasonable? From my point of view, the worst case which isn't 
> in the
>>>>  domain of the plain ridiculous would be that someone uses a 32-bit
>>>>  float representation of a board which is about 1000mm across - that
>>>>  would give a worst case expectation of about 1 micron. I would
>>>>  imagine even 10 microns should be acceptable given modern
>>>>  manufacturing techniques and limitations of reality.
>>>> 
>>>>  - Cirilo
>>> 
>>>  You can try:
>>>  prox = Mils2iu( 1 );
>>> 
>>>  One mil is certainly acceptable, and should be enough for rounding
>>>  issues when arcs are converted from dxf files.
>>> 
>> 
>>  This may solve the 3D drawing issue but is it acceptable to export to
>>  specctra with an unclosed board outline?  I seem to remember there being
>>  some debate as to whether or not that is valid.  The other option is
>>  attempt to close any gaps in the board outline only for 3D rendering
>>  purposes and enforce a closed board outline for specctra export.
> 
> You are right.
> I'll make more tests soon with exported dsn files.
> 
> However 3D drawing needs valid polygons to display the board outlines
> and holes.
> And specctra export uses prox = Mils2iu( 10 ); to find holes inside the
> board.
> This is the reasons I proposed prox = Mils2iu( 1 ); in main outlines
> calculations.
> 
> -- 
> Jean-Pierre CHARRAS
> 
> 


MCAD software can also be very strict with the IDF outline; what I did for IDF was to force the end segments to be the same by writing only 1 point from each segment except for the first point (2 points) and the last point (none). fillBOUNDARY() also does this; if we patch line 1101 (test for closed polygon) to replace the last point with the first point then there will be no problem for specctra either.

- Cirilo