Version: Rhino 4

The following sample code demonstrates how to use the CArgsRhinoSweep2 class and the RhinoSweep2 SDK function. The definitions of these can be found in rhinoSdkSweep.h.

Note, this example does not perform any curve sorting or direction matching. This is the responsibility of the the SDK developer. The following image shows an example that will work:

// Helper function to calculate rail parameters
bool GetShapeParameterOnRail( 
  const ON_Curve& shape, 
  const ON_Curve& rail, 
  double tol, 
  double& t 
  )
{
  ON_Interval rail_domain = rail.Domain();
 
  // Test start point
  bool rc = rail.GetClosestPoint( shape.PointAtStart(), &t, tol );
  if( rc )
  {
    if( rail.IsClosed() )
    {
      if( fabs(t - rail_domain.Max()) < ON_SQRT_EPSILON )
        t = rail_domain.Min();
      if( fabs(t - rail_domain.Min()) < ON_SQRT_EPSILON )
        t = rail_domain.Min();
    }
    return true;
  }
 
  // Test end point
  rc = rail.GetClosestPoint( shape.PointAtEnd(), &t, tol );
  if( rc )
  {
    if( rail.IsClosed() )
    {
      if( fabs(t - rail_domain.Max()) < ON_SQRT_EPSILON )
        t = rail_domain.Min();
      if( fabs(t - rail_domain.Min()) < ON_SQRT_EPSILON )
        t = rail_domain.Min();
    }
    return true;
  }
 
  // Try intersecting...
  ON_SimpleArray<ON_X_EVENT> x;
  if( 1 == rail.IntersectCurve(&shape, x, tol, 0.0) && x[0].IsPointEvent() )
  {
    t = x[0].m_a[0];
    if( rail.IsClosed() )
    {
      if( fabs(t - rail_domain.Max()) < ON_SQRT_EPSILON )
        t = rail_domain.Min();
    }
    return true;
  }
 
  return false;
}
 
// RhinoSweep2 wrapper function
bool MySweep2( 
  const ON_Curve* Rail1, 
  const CRhinoObject* Rail1_obj, 
  const ON_Curve* Rail2, 
  const CRhinoObject* Rail2_obj, 
  ON_SimpleArray<const ON_Curve*> sCurves, 
  ON_SimpleArray<ON_Brep*>& Sweep2_Breps 
  )
{
  if( 0 == Rail1 | 0 == Rail1_obj )
    return false;
 
  if( 0 == Rail2 | 0 == Rail2_obj )
    return false;
 
  CRhinoDoc* doc = RhinoApp().ActiveDoc();
  if( 0 == doc )
    return false;
 
  // Define a new class that contains sweep2 arguments
  CArgsRhinoSweep2 args;
 
  // Set the 2 rails
  CRhinoPolyEdge Edge1, Edge2;
  Edge1.Create( Rail1, Rail1_obj );
  Edge2.Create( Rail2, Rail2_obj );
 
  // Ok, we can at least do some rail direction matching
  if( !RhinoDoCurveDirectionsMatch(&Edge1, &Edge2) )
    Edge2.Reverse();
 
  // Add rails to sweep arguments
  args.m_rail_curves[0] = &Edge1;
  args.m_rail_curves[1] = &Edge2;
 
  args.m_rail_pick_points[0] = ON_UNSET_POINT;
  args.m_rail_pick_points[1] = ON_UNSET_POINT;
 
  // To create a closed sweep, you need to have:
  //  1. Two closed rail curves and and a single shape curve, or
  //  2. Set CArgsRhinoSweep2::m_bClosed = true
  args.m_bClosed = false;
 
  double tol = doc->AbsoluteTolerance();
 
  // Loop through sections to set parameters
  for( int i = 0; i < sCurves.Count(); i++ )
  {
    const ON_Curve* sCurve = sCurves[i];
    if( 0 == sCurve )
      continue;
 
    // Add to shapes
    args.m_shape_curves.Append( sCurve );
 
    // Cook up some rail parameters
    double t0 = 0.0;
    if( !GetShapeParameterOnRail(*sCurve, Edge1, tol, t0) )
      return false;
    args.m_rail_params[0].Append( t0 );
 
    double t1 = 0.0;
    if( !GetShapeParameterOnRail(*sCurve, Edge2, tol, t1) )
      return false;
    args.m_rail_params[1].Append( t1 );
  }
 
  // Set the rest of parameters
  args.m_simplify = 0;
  args.m_bSimpleSweep = false;
  args.m_bSameHeight = false;
  args.m_rebuild_count = -1; //Sample point count for rebuilding shapes
  args.m_refit_tolerance = tol;
  args.m_sweep_tolerance = tol;
  args.m_angle_tolerance = doc->AngleToleranceRadians();
 
  // Sweep2
  return RhinoSweep2(args, Sweep2_Breps) ? true : false;
}
 
// Test command that uses the above functions.
CRhinoCommand::result CCommandTest::RunCommand( const CRhinoCommandContext& context )
{
  // Select first rail curve
  CRhinoGetObject go1;
  go1.SetCommandPrompt( L"Select first rail curve" );
  go1.SetGeometryFilter( CRhinoGetObject::curve_object );
  go1.EnablePreSelect( false );
  go1.GetObjects( 1, 1 );
  if( go1.CommandResult() != success )
    return go1.CommandResult();
 
  const CRhinoObject* Rail1_obj = go1.Object(0).Object();
  const ON_Curve* Rail1 = go1.Object(0).Curve();
  if( 0 == Rail1_obj | 0 == Rail1 )
    return failure;
 
  // Select second rail curve
  CRhinoGetObject go2;
  go2.SetCommandPrompt( L"Select second rail curve" );
  go2.SetGeometryFilter( CRhinoGetObject::curve_object );
  go2.EnablePreSelect( false );
  go2.EnableDeselectAllBeforePostSelect( false );
  go2.GetObjects( 1, 1 );
  if( go2.CommandResult() != success )
    return go2.CommandResult();
 
  const CRhinoObject* Rail2_obj = go2.Object(0).Object();
  const ON_Curve* Rail2 = go2.Object(0).Curve();
  if( 0 == Rail2_obj | 0 == Rail2 )
    return failure;
 
  // Select cross section curves
  CRhinoGetObject gx;
  gx.SetCommandPrompt( L"Select cross section curves" );
  gx.SetGeometryFilter( CRhinoGetObject::curve_object );
  gx.EnablePreSelect( false );
  gx.EnableDeselectAllBeforePostSelect( false );
  gx.GetObjects( 1, 0 );
  if( gx.CommandResult() != success )
    return gx.CommandResult();
 
  ON_SimpleArray<const ON_Curve*> sCurves;
  int i;
  for( i = 0; i < gx.ObjectCount(); i++ )
  {
    const ON_Curve* sCurve = gx.Object(i).Curve();
    if( sCurve )
      sCurves.Append( sCurve );
  }
 
  // Call MySweep2 function
  ON_SimpleArray<ON_Brep*> Sweep2_Breps;
  if( MySweep2(Rail1, Rail1_obj, Rail2, Rail2_obj, sCurves, Sweep2_Breps) )
  {
    // Add to context then delete
    for( i = 0; i < Sweep2_Breps.Count(); i++ )
    {
      ON_Brep* brep = Sweep2_Breps[i];
      if( brep )
      {
        context.m_doc.AddBrepObject( *brep );
        delete Sweep2_Breps[i]; // Don't leak...
        Sweep2_Breps[i] = 0;
      }
    }
 
    context.m_doc.Redraw();
  }
 
  return success;
}

Public Overrides Function RunCommand(ByVal context As RhinoCommandContext) _
  'Select first rail curve
  Dim go As New MRhinoGetObject()
  go.SetCommandPrompt("Select first rail curve for Sweep 2")
  go.SetGeometryFilter(IRhinoGetObject.GEOMETRY_TYPE_FILTER.curve_object)
  go.GetObjects(1, 1)
  If (go.CommandResult() <> IRhinoCommand.result.success) Then
    Return go.CommandResult()
  End If
 
  Dim rail1_ref As MRhinoObjRef = go.Object(0)
  Dim rail1_obj As IRhinoObject = rail1_ref.Object()
  Dim rail1_crv As IOnCurve = rail1_ref.Curve()
  If (rail1_obj Is Nothing Or rail1_crv Is Nothing) Then
    Return IRhinoCommand.result.failure
  End If
 
  'Select second rail curve
  Dim go1 As New MRhinoGetObject()
  go1.EnablePreSelect(False)
  go1.EnableDeselectAllBeforePostSelect(False)
  go1.SetCommandPrompt("Select second rail curve for Sweep 2")
  go1.SetGeometryFilter(IRhinoGetObject.GEOMETRY_TYPE_FILTER.curve_object)
  go1.GetObjects(1, 1)
  If (go1.CommandResult() <> IRhinoCommand.result.success) Then
    Return go1.CommandResult()
  End If
 
  Dim rail2_ref As MRhinoObjRef = go1.Object(0)
  Dim rail2_obj As IRhinoObject = rail2_ref.Object()
  Dim rail2_crv As IOnCurve = rail2_ref.Curve()
  If (rail2_obj Is Nothing Or rail2_crv Is Nothing) Then
    Return IRhinoCommand.result.failure
  End If
 
  Dim gx As New MRhinoGetObject()
  gx.SetCommandPrompt("Select cross section curves")
  gx.SetGeometryFilter(IRhinoGetObject.GEOMETRY_TYPE_FILTER.curve_object)
  gx.EnablePreSelect(False)
  gx.EnableDeselectAllBeforePostSelect(False)
  gx.GetObjects(1, 0)
  If (gx.CommandResult() <> IRhinoCommand.result.success) Then
    Return gx.CommandResult()
  End If
 
  Dim curves As New List(Of IOnCurve)
  For i As Integer = 0 To gx.ObjectCount() - 1
    Dim obj_ref As MRhinoObjRef = gx.Object(i)
    Dim crv As IOnCurve = obj_ref.Curve()
    If (crv IsNot Nothing) Then
      curves.Add(crv)
    End If
  Next
 
  Dim Sweep2_Breps As New List(Of OnBrep)
  Sweep2(rail1_crv, rail2_crv, curves, Sweep2_Breps)
 
  'Add to document
  For Each b As OnBrep In Sweep2_Breps
    context.m_doc.AddBrepObject(b)
  Next
 
  context.m_doc.Redraw()
  Return IRhinoCommand.result.success
 
End Function
 
'Sweep2 function
'----------------
Sub Sweep2( ByVal Rail1 As IOnCurve, _
            ByVal Rail2 As IOnCurve, _
            ByVal sCurves As List(Of IOnCurve), _
            ByRef Sweep2_Breps As List(Of OnBrep))
  'Define a new class that contains sweep2 arguments
  Dim args As New MArgsRhinoSweep2
 
  'Set the 2 rails
  Dim Edge1 As New MRhinoPolyEdge
  Dim Edge2 As New MRhinoPolyEdge
  Edge1.Append(Rail1.DuplicateCurve())
  Edge2.Append(Rail2.DuplicateCurve())
 
  'Add rails to sweep arguments
  args.m_rail_curves(0) = Edge1
  args.m_rail_curves(1) = Edge2
  args.m_bClosed = False
 
  Dim section_curves As New List(Of OnCurve)
 
  'Loop through sections to set parameters
  For Each Section As IOnCurve In sCurves
    Dim sCurve As OnCurve = Section.DuplicateCurve()
    section_curves.Add(sCurve)
 
    Dim t0 As Double = 0
    If Not Edge1.GetClosestPoint(sCurve.PointAtStart(), t0) Then
      If Not Edge1.GetClosestPoint(sCurve.PointAtEnd(), t0) Then
        Dim s As Double = 0
        sCurve.GetNormalizedArcLengthPoint(0.5, s)
        Edge1.GetClosestPoint(sCurve.PointAt(s), t0)
      End If
    End If
    args.m_rail_params(0).Append(t0)
 
    Dim t1 As Double = 0
    If Not Edge2.GetClosestPoint(sCurve.PointAtStart(), t1) Then
      If Not Edge2.GetClosestPoint(sCurve.PointAtEnd(), t1) Then
        Dim s As Double = 0
        sCurve.GetNormalizedArcLengthPoint(0.5, s)
        Edge2.GetClosestPoint(sCurve.PointAt(s), t1)
      End If
    End If
    args.m_rail_params(1).Append(t1)
  Next
 
  'Set shapes
  args.m_shape_curves = section_curves.ToArray
 
  'Set the rest of parameters
  args.m_simplify = 0
  args.m_bSimpleSweep = False
  args.m_bSameHeight = False
  args.m_rebuild_count = -1 'Sample point count for rebuilding shapes
  args.m_refit_tolerance = RMA.Rhino.RhUtil.RhinoApp.ActiveDoc.AbsoluteTolerance()
  args.m_sweep_tolerance = RMA.Rhino.RhUtil.RhinoApp.ActiveDoc.AbsoluteTolerance()
  args.m_angle_tolerance = RMA.Rhino.RhUtil.RhinoApp.ActiveDoc.AngleToleranceRadians()
 
  Dim sBreps() As OnBrep = Nothing
  If (RhUtil.RhinoSweep2(args, sBreps)) Then
    For Each b As OnBrep In sBreps
      Sweep2_Breps.Add(b)
    Next
  End If
 
  Return
End Sub