STEP export: in board outlines, export Circles as Cylinders.

Other arcs (not 360 deg arcs) are still exported as polylines

pcbnew/convert_shape_list_to_polygon.cpp

@@ -238,30 +238,22 @@ bool ConvertOutlineToPolygon( std::vector<PCB_SHAPE*>& aShapeList, SHAPE_POLY_SE
         }
         else if( graphic->GetShape() == SHAPE_T::CIRCLE )
         {
-            // make a circle by segments;
             VECTOR2I center = graphic->GetCenter();
-            VECTOR2I start = center;
             int      radius  = graphic->GetRadius();
-            int      steps   = GetArcToSegmentCount( radius, aErrorMax, FULL_CIRCLE );
-            VECTOR2I nextPt;
-
+            VECTOR2I start = center;
             start.x += radius;
 
-            for( int step = 0; step < steps; ++step )
-            {
-                nextPt = start;
-                RotatePoint( nextPt, center, ANGLE_360 * step / steps );
-                currContour.Append( nextPt );
-
-                if( firstPt )
-                    firstPt = false;
-                else
-                    shapeOwners[ std::make_pair( prevPt, nextPt ) ] = graphic;
-
-                prevPt = nextPt;
-            }
-
+            // Add 360 deg Arc in currContour
+            SHAPE_ARC arc360( center, start, ANGLE_360, 0 );
+            currContour.Append( arc360, aErrorMax );
             currContour.SetClosed( true );
+
+            // set shapeOwners for currContour points created by appending the arc360:
+            for( int ii = 1; ii < currContour.PointCount(); ++ii )
+            {
+                shapeOwners[ std::make_pair( currContour.CPoint( ii-1 ),
+                                             currContour.CPoint( ii ) ) ] = graphic;
+            }
         }
         else if( graphic->GetShape() == SHAPE_T::RECT )
         {

pcbnew/exporters/step/step_pcb_model.cpp

@@ -415,6 +415,56 @@ bool STEP_PCB_MODEL::isBoardOutlineValid()
     return m_pcb_labels.size() > 0;
 }
 
+// A helper function to know if a SHAPE_LINE_CHAIN is encoding a circle
+static bool IsChainCircle( const SHAPE_LINE_CHAIN& aChain )
+{
+    // If aChain is a circle it
+    // - contains only one arc
+    // - this arc has the same start and end point
+    const std::vector<SHAPE_ARC>& arcs = aChain.CArcs();
+
+    if( arcs.size() == 1 )
+    {
+        const SHAPE_ARC& arc = arcs[0];
+
+        if( arc. GetP0() == arc.GetP1() )
+            return true;
+    }
+
+    return false;
+}
+
+bool STEP_PCB_MODEL::MakeShapeAsCylinder( TopoDS_Shape& aShape,
+                                          const SHAPE_LINE_CHAIN& aChain, double aThickness,
+                                          double aZposition, const VECTOR2D& aOrigin )
+{
+    if( !aShape.IsNull() )
+        return false; // there is already data in the shape object
+
+    if( !aChain.IsClosed() )
+        return false; // the loop is not closed
+
+    const std::vector<SHAPE_ARC>& arcs = aChain.CArcs();
+    const SHAPE_ARC& arc = arcs[0];
+
+    TopoDS_Shape base_shape;
+    base_shape = BRepPrimAPI_MakeCylinder(
+                        pcbIUScale.IUTomm( arc.GetRadius() ), aThickness ).Shape();
+    gp_Trsf shift;
+    shift.SetTranslation( gp_Vec( pcbIUScale.IUTomm( arc.GetCenter().x - aOrigin.x ),
+                                  -pcbIUScale.IUTomm( arc.GetCenter().y - aOrigin.y ),
+                                  aZposition ) );
+    BRepBuilderAPI_Transform round_shape( base_shape, shift );
+    aShape = round_shape;
+
+    if( aShape.IsNull() )
+    {
+        ReportMessage( wxT( "failed to create a cylinder vertical shape\n" ) );
+        return false;
+    }
+
+    return true;
+}
 
 bool STEP_PCB_MODEL::MakeShape( TopoDS_Shape& aShape, const SHAPE_LINE_CHAIN& aChain,
                                 double aThickness, double aZposition, const VECTOR2D& aOrigin )
@@ -425,6 +475,10 @@ bool STEP_PCB_MODEL::MakeShape( TopoDS_Shape& aShape, const SHAPE_LINE_CHAIN& aC
     if( !aChain.IsClosed() )
         return false; // the loop is not closed
 
+    // a SHAPE_LINE_CHAIN that is in fact a circle (one 360deg arc) is exported as cylinder
+    if( IsChainCircle( aChain ) )
+        return MakeShapeAsCylinder( aShape, aChain, aThickness, aZposition, aOrigin );
+
     BRepBuilderAPI_MakeWire wire;
     bool success = true;
 

pcbnew/exporters/step/step_pcb_model.h

@@ -111,9 +111,30 @@ public:
     // create the PCB model using the current outlines and drill holes
     bool CreatePCB( SHAPE_POLY_SET& aOutline, VECTOR2D aOrigin );
 
-    bool MakeShape( TopoDS_Shape& aShape, const SHAPE_LINE_CHAIN& chain, double aThickness,
+    /**
+     * Convert a SHAPE_LINE_CHAIN (closed) to a TopoDS_Shape (polygonal vertical prism)
+     * @param aShape is the TopoDS_Shape to initialize (must be empty)
+     * @param aChain is a closed SHAPE_LINE_CHAIN (a polygon)
+     * @param aThickness is the height of the created prism
+     * @param aOrigin is the origin of the coordinates
+     * @return true if success
+     */
+    bool MakeShape( TopoDS_Shape& aShape, const SHAPE_LINE_CHAIN& aChain, double aThickness,
                     double aZposition, const VECTOR2D& aOrigin );
 
+    /**
+     * Convert a SHAPE_LINE_CHAIN containing only one 360 deg arc to a TopoDS_Shape
+     * ( vertical cylinder)
+     * it is a specialized version of MakeShape()
+     * @param aShape is the TopoDS_Shape to initialize (must be empty)
+     * @param aChain is a closed SHAPE_LINE_CHAIN, image of a circle: containing one 360 deg arc
+     * @param aThickness is the height of the created cylinder
+     * @param aOrigin is the origin of the coordinates
+     * @return true if success
+     */
+    bool MakeShapeAsCylinder( TopoDS_Shape& aShape, const SHAPE_LINE_CHAIN& aChain,
+                              double aThickness, double aZposition, const VECTOR2D& aOrigin );
+
 #ifdef SUPPORTS_IGES
     // write the assembly model in IGES format
     bool WriteIGES( const wxString& aFileName );