Fixes in build board outlines as polygon and convert_shape_list_to_polygon:

- Ensure Bezier curves have their polygon build before use it.
- When building board outlines as polygon the same chaining epsilon value
for DRC, export step and 3D view (default 0.01mm).
Fixes #14115
https://gitlab.com/kicad/code/kicad/issues/14115
Fixes #14009
https://gitlab.com/kicad/code/kicad/issues/14009

3d-viewer/3d_canvas/board_adapter.cpp

@@ -2,7 +2,7 @@
  * This program source code file is part of KiCad, a free EDA CAD application.
  *
  * Copyright (C) 2015-2022 Mario Luzeiro <[email protected]>
- * Copyright (C) 1992-2022 KiCad Developers, see AUTHORS.txt for contributors.
+ * Copyright (C) 1992-2023 KiCad Developers, see AUTHORS.txt for contributors.
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -671,7 +671,8 @@ bool BOARD_ADAPTER::createBoardPolygon( wxString* aErrorMsg )
             return false;
         }
 
-        int chainingEpsilon = pcbIUScale.mmToIU( 0.02 ); // max dist from one endPt to next startPt
+        // max dist from one endPt to next startPt
+        int chainingEpsilon = m_board->GetOutlinesChainingEpsilon();
 
         success = BuildFootprintPolygonOutlines( m_board, m_board_poly,
                                                  m_board->GetDesignSettings().m_MaxError,

pcbnew/board.cpp

@@ -78,6 +78,10 @@ BOARD::BOARD() :
         m_designSettings( new BOARD_DESIGN_SETTINGS( nullptr, "board.design_settings" ) ),
         m_NetInfo( this )
 {
+    // A too small value do not allow connecting 2 shapes (i.e. segments) not exactly connected
+    // A too large value do not allow safely connecting 2 shapes like very short segments.
+    m_outlinesChainingEpsilon = pcbIUScale.mmToIU( DEFAULT_CHAINING_EPSILON_MM );
+
     // we have not loaded a board yet, assume latest until then.
     m_fileFormatVersionAtLoad = LEGACY_BOARD_FILE_VERSION;
 
@@ -1968,7 +1972,8 @@ ZONE* BOARD::AddArea( PICKED_ITEMS_LIST* aNewZonesList, int aNetcode, PCB_LAYER_
 bool BOARD::GetBoardPolygonOutlines( SHAPE_POLY_SET& aOutlines,
                                      OUTLINE_ERROR_HANDLER* aErrorHandler )
 {
-    int chainingEpsilon = pcbIUScale.mmToIU( 0.02 ); // max dist from one endPt to next startPt
+    // max dist from one endPt to next startPt: use the current value
+    int chainingEpsilon = GetOutlinesChainingEpsilon();
 
     bool success = BuildBoardPolygonOutlines( this, aOutlines, GetDesignSettings().m_MaxError,
                                               chainingEpsilon, aErrorHandler );

pcbnew/board.h

@@ -2,7 +2,7 @@
  * This program source code file is part of KiCad, a free EDA CAD application.
  *
  * Copyright (C) 2007 Jean-Pierre Charras, [email protected]
- * Copyright (C) 1992-2022 KiCad Developers, see AUTHORS.txt for contributors.
+ * Copyright (C) 1992-2023 KiCad Developers, see AUTHORS.txt for contributors.
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -61,6 +61,10 @@ class COMPONENT;
 class PROJECT;
 class PROGRESS_REPORTER;
 
+// The default value for m_outlinesChainingEpsilon to convert a board outlines to polygons
+// It is the max dist between 2 end points to see them connected
+#define DEFAULT_CHAINING_EPSILON_MM 0.01
+
 // Forward declare endpoint from class_track.h
 enum ENDPOINT_T : int;
 
@@ -652,6 +656,16 @@ public:
                                   OUTLINE_ERROR_HANDLER* aErrorHandler = nullptr );
 
     /**
+     * @return a epsilon value that is the max distance between 2 points to see them
+     * at the same coordinate when building the board outlines and tray to connect 2 end points
+     * when buildind the outlines of the board
+     * Too small value do not allow connecting 2 shapes (i.e. segments) not exactly connected
+     * Too large value do not allow safely connecting 2 shapes like very short segments.
+     */
+    int GetOutlinesChainingEpsilon() { return( m_outlinesChainingEpsilon ); }
+    void SetOutlinesChainingEpsilon( int aValue) { m_outlinesChainingEpsilon = aValue; }
+
+   /**
      * Build a set of polygons which are the outlines of copper items (pads, tracks, vias, texts,
      * zones).
      *
@@ -1171,6 +1185,10 @@ private:
 
     friend class PCB_EDIT_FRAME;
 
+
+    /// the max distance between 2 end point to see them connected when building the board outlines
+    int m_outlinesChainingEpsilon;
+
     /// What is this board being used for
     BOARD_USE           m_boardUse;
     int                 m_timeStamp;                // actually a modification counter

pcbnew/convert_shape_list_to_polygon.cpp

@@ -3,7 +3,7 @@
  *
  * Copyright (C) 2017 Jean-Pierre Charras, jp.charras at wanadoo.fr
  * Copyright (C) 2015 SoftPLC Corporation, Dick Hollenbeck <[email protected]>
- * Copyright (C) 1992-2022 KiCad Developers, see AUTHORS.txt for contributors.
+ * Copyright (C) 1992-2023 KiCad Developers, see AUTHORS.txt for contributors.
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -400,11 +400,21 @@ bool ConvertOutlineToPolygon( std::vector<PCB_SHAPE*>& aShapeList, SHAPE_POLY_SE
                             reverse = true;
                         }
 
+                        // Ensure the approximated Bezier shape is built
+                        // a good value is between (Bezier curve width / 2) and (Bezier curve width)
+                        // ( and at least 0.05 mm to avoid very small segments)
+                        int min_segm_lenght = std::max( pcbIUScale.mmToIU( 0.05 ), graphic->GetWidth() );
+                        graphic->RebuildBezierToSegmentsPointsList( min_segm_lenght );
+
                         if( reverse )
                         {
                             for( int jj = graphic->GetBezierPoints().size()-1; jj >= 0; jj-- )
                             {
                                 const VECTOR2I& pt = graphic->GetBezierPoints()[jj];
+
+                                if( prevPt == pt )
+                                    continue;
+
                                 currContour.Append( pt );
                                 shapeOwners[ std::make_pair( prevPt, pt ) ] = graphic;
                                 prevPt = pt;
@@ -414,6 +424,9 @@ bool ConvertOutlineToPolygon( std::vector<PCB_SHAPE*>& aShapeList, SHAPE_POLY_SE
                         {
                             for( const VECTOR2I& pt : graphic->GetBezierPoints() )
                             {
+                                if( prevPt == pt )
+                                    continue;
+
                                 currContour.Append( pt );
                                 shapeOwners[ std::make_pair( prevPt, pt ) ] = graphic;
                                 prevPt = pt;

pcbnew/drc/drc_test_provider_misc.cpp

@@ -1,7 +1,7 @@
 /*
  * This program source code file is part of KiCad, a free EDA CAD application.
  *
- * Copyright (C) 2004-2022 KiCad Developers.
+ * Copyright (C) 2004-2023 KiCad Developers.
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -94,9 +94,9 @@ void DRC_TEST_PROVIDER_MISC::testOutline()
                 errorHandled = true;
             };
 
-    // Use a really tight chaining epsilon here so that we report errors that might affect
+    // Use the standard chaining epsilon here so that we report errors that might affect
     // other tools (such as STEP export).
-    constexpr int chainingEpsilon = pcbIUScale.mmToIU( 0.02 ) / 100;
+    int chainingEpsilon = m_board->GetOutlinesChainingEpsilon();
 
     if( !BuildBoardPolygonOutlines( m_board, dummyOutline, m_board->GetDesignSettings().m_MaxError,
                                     chainingEpsilon, &errorHandler ) )

pcbnew/exporters/step/exporter_step.cpp

@@ -3,7 +3,7 @@
  *
  * Copyright (C) 2022 Mark Roszko <[email protected]>
  * Copyright (C) 2016 Cirilo Bernardo <[email protected]>
- * Copyright (C) 2016-2022 KiCad Developers, see AUTHORS.txt for contributors.
+ * Copyright (C) 2016-2023 KiCad Developers, see AUTHORS.txt for contributors.
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -263,8 +263,10 @@ bool EXPORTER_STEP::composePCB()
     m_pcbModel->SetBoardColor( m_solderMaskColor.r, m_solderMaskColor.g, m_solderMaskColor.b );
 
     m_pcbModel->SetPCBThickness( m_boardThickness );
-    m_pcbModel->SetMinDistance(
-            std::max( m_params.m_minDistance, STEPEXPORT_MIN_ACCEPTABLE_DISTANCE ) );
+
+    // Set the min distance betewenn 2 points for OCC to see these 2 points as merged
+    double minDistmm = std::max( m_params.m_minDistance, STEPEXPORT_MIN_ACCEPTABLE_DISTANCE );
+    m_pcbModel->SetMinDistance( minDistmm );
 
     m_pcbModel->SetMaxError( m_board->GetDesignSettings().m_MaxError );
 
@@ -273,6 +275,10 @@ bool EXPORTER_STEP::composePCB()
 
     ReportMessage( wxT( "Create PCB solid model\n" ) );
 
+    wxString msg;
+    msg.Printf( wxT( "Board outline: find %d initial points\n" ), pcbOutlines.FullPointCount() );
+    ReportMessage( msg );
+
     if( !m_pcbModel->CreatePCB( pcbOutlines, origin ) )
     {
         ReportMessage( wxT( "could not create PCB solid model\n" ) );