kicad-developers team mailing list archive

[Forrest Voight <forrest.voight@xxxxxxxxx>]

I found another related problem with oval pads: tracks intersecting
with oval pads are sometimes *not* detected as DRC violations.

Looking at the below screenshot or PCB, the narrow track should *but
does not* trigger a DRC violation in its current position, while it
does generate a violation if dragged 2mm down to intersect with the
center of the large oval pad.

I've linked a patch that fixes the issue.

Board: http://u.forre.st/kicad_bug2/track_x_oval_pad_failure.kicad_pcb
Board screenshot: http://u.forre.st/kicad_bug2/track_x_oval_pad_failure.png
Patch (also below):
http://u.forre.st/kicad_bug2/0001-Fix-track-rotated-oval-pad-collision-detection.patch

As a related question, how hard is it to get committer access? I have
several more minor fixes that I'd like to bring in.


>From ec6adcfb0d6b5583e132264cb84a3ba897a5da2b Mon Sep 17 00:00:00 2001
From: Forrest Voight <forrest@xxxxxxxx>
Date: Mon, 22 Jan 2018 13:50:33 -0500
Subject: [PATCH] Fix track/rotated oval pad collision detection

---
 pcbnew/drc_clearance_test_functions.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/pcbnew/drc_clearance_test_functions.cpp
b/pcbnew/drc_clearance_test_functions.cpp
index e395e7d..1ab6af0 100644
--- a/pcbnew/drc_clearance_test_functions.cpp
+++ b/pcbnew/drc_clearance_test_functions.cpp
@@ -1052,6 +1052,9 @@ bool DRC::checkClearanceSegmToPad( const D_PAD*
aPad, int aSegmentWidth, int aMi
         {
             std::swap( padHalfsize.x, padHalfsize.y );
             orient = AddAngles( orient, 900 );
+            // recompute start/endPoint since they depend on orient
+            RotatePoint( &startPoint, m_padToTestPos, -900 );
+            RotatePoint( &endPoint, m_padToTestPos, -900 );
         }

         // here, padHalfsize.x is the radius of rounded ends.
-- 
2.7.4



On Sun, May 17, 2015 at 7:00 AM, jp charras <jp.charras@xxxxxxxxxx> wrote:
> Le 15/05/2015 23:12, Forrest Voight a écrit :
>> (This is also at https://bugs.launchpad.net/kicad/+bug/1455345)
>>
>> Minimal example screenshot: http://u.forre.st/u/fiyaqxjg/drc.png
>> Minimal example board file: http://u.forre.st/u/kjzegyao/drc.kicad_pcb
>>
>> Two pads (one a circle and one an oval) cause a false DRC violation in
>> certain arrangements.
>>
>> I am reasonably certain that this is due to the rectangle part of the
>> segment-oval test in DRC::checkClearanceSegmToPad. This function is
>> called by DRC::checkClearancePadToPad with the circle pad having been
>> transformed to a zero-length segment and the oval pad remaining as is.
>> Then, DRC::checkClearanceSegmToPad looks at the oval pad as two
>> circles and a rectangle, testing the segment against each, grown
>> according to the segment's width and the clearance. The rectangle is
>> grown at each end of its short axis by half the width of the segment
>> (the radius of the circular pad in this case) plus the clearance
>> (which makes sense) and grown at each end of its long axis by half the
>> width of the segment (!!!).
>>
>> Growing the rectangular part of the pad along its long axis by
>> anything is wrong because the dilation of a rectangle is a rounded
>> rectangle, but by growing it along both axes, we form a shape that is
>> bigger than what it should be (it has corners that shouldn't be
>> there). We don't need to grow it along its long axis at all, because
>> intersections near the ends of the pad are taken care of by the circle
>> tests.
>>
>> A patch that fixes this issue, as I see it, is here:
>
> Good catch!
>
> I fixed that (using your patch) with a minor code cleaning in rev 5656.
>
> Thanks.
>
>
> --
> Jean-Pierre CHARRAS
>
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