Nektar::NekMeshUtils::CADSurf Class Reference

class for handleing a cad surface More...

#include <CADSurf.h>

Inheritance diagram for Nektar::NekMeshUtils::CADSurf:

Collaboration diagram for Nektar::NekMeshUtils::CADSurf:

Public Member Functions
	CADSurf (int i, TopoDS_Shape in, std::vector< EdgeLoop > ein)
	Default constructor. More...
	~CADSurf ()
std::vector< EdgeLoop >	GetEdges ()
	Get the IDs of the edges which bound the surface. More...
Array< OneD, NekDouble >	GetBounds ()
	Get the limits of the parametric space for the surface. More...
Array< OneD, NekDouble >	N (Array< OneD, NekDouble > uv)
	Get the normal vector at parametric point u,v. More...
Array< OneD, NekDouble >	D1 (Array< OneD, NekDouble > uv)
	Get the set of first derivatives at parametric point u,v. More...
Array< OneD, NekDouble >	D2 (Array< OneD, NekDouble > uv)
	Get the set of second derivatives at parametric point u,v. More...
Array< OneD, NekDouble >	P (Array< OneD, NekDouble > uv)
	Get the x,y,z at parametric point u,v. More...
Array< OneD, NekDouble >	locuv (Array< OneD, NekDouble > p)
	Performs a reverse look up to find u,v and x,y,z. More...
bool	IsPlane ()
	returns true if the surface is flat (2D) More...
void	SetReverseNomral ()
	sets the flag to reverse the normal for this suface, this is determined in cadsystem and ensures all surface normals, point internaly More...
bool	IsReversedNormal ()
void	SetTwoC ()
	surface needs to know if it is bounded by only two curves More...
bool	GetTwoC ()
	query two curves More...
NekDouble	DistanceTo (Array< OneD, NekDouble > p)
	does unconstrained locuv to project point from anywhere More...
void	ProjectTo (Array< OneD, NekDouble > &tp, Array< OneD, NekDouble > &uv)
NekDouble	Curvature (Array< OneD, NekDouble > uv)
	returns curvature at point uv More...
Public Member Functions inherited from Nektar::NekMeshUtils::CADObj
	CADObj ()
	Default constructor. More...
virtual	~CADObj ()
int	GetId ()
	Return ID of the vertex. More...
cadType	GetType ()

Private Member Functions
void	Test (Array< OneD, NekDouble > uv)
	Function which tests the the value of uv used is within the surface. More...
	Handle (Geom_Surface) m_s
	Alternate OpenCascade object for surface. Used by reverse lookup. More...

Private Attributes
bool	m_correctNormal
	normal More...
bool	m_hasTwoCurves
	flag to alert the mesh generation to a potential problem is both curves have only two points in the mesh More...
BRepAdaptor_Surface	m_occSurface
	OpenCascade object for surface. More...
std::vector< EdgeLoop >	m_edges
	List of bounding edges in loops with orientation. More...

Friends
class	MemoryManager< CADSurf >

Additional Inherited Members
Protected Attributes inherited from Nektar::NekMeshUtils::CADObj
int	m_id
	ID of the vert. More...
cadType	m_type
	type of the cad object More...

Detailed Description

class for handleing a cad surface

Definition at line 72 of file CADSurf.h.

Constructor & Destructor Documentation

Nektar::NekMeshUtils::CADSurf::CADSurf	(	int	i,
		TopoDS_Shape	in,
		std::vector< EdgeLoop >	ein
	)

Default constructor.

Definition at line 47 of file CADSurf.cpp.

References m_correctNormal, m_hasTwoCurves, Nektar::NekMeshUtils::CADObj::m_id, m_occSurface, Nektar::NekMeshUtils::CADObj::m_type, and Nektar::NekMeshUtils::surf.

                                                             : m_edges(ein)
{
    // this bit of code changes the units of the cad from mm opencascade
    // defualt to m
    gp_Trsf transform;
    gp_Pnt ori(0.0, 0.0, 0.0);
    transform.SetScale(ori, 1.0 / 1000.0);
    TopLoc_Location mv(transform);
    m_s = BRep_Tool::Surface(TopoDS::Face(in));
    in.Move(mv);
    m_occSurface    = BRepAdaptor_Surface(TopoDS::Face(in));
    m_correctNormal = true;
    m_hasTwoCurves  = false;
    m_id            = i;
    m_type          = surf;
}

Nektar::NekMeshUtils::CADSurf::~CADSurf ( )

inline

Definition at line 82 of file CADSurf.h.

{};

Member Function Documentation

NekDouble Nektar::NekMeshUtils::CADSurf::Curvature

(

Array< OneD, NekDouble >

uv

)

returns curvature at point uv

Definition at line 144 of file CADSurf.cpp.

References D2(), N(), and Test().

{
    Test(uv);

    Array<OneD, NekDouble> n = N(uv);

    // a zero normal occurs at a signularity, CurvaturePoint
    // cannot be sampled here
    if (n[0] == 0 && n[1] == 0 && n[2] == 0)
    {
        return 0.0;
    }

    Array<OneD, NekDouble> r = D2(uv);

    // metric and curvature tensors
    NekDouble E = r[3] * r[3] + r[4] * r[4] + r[5] * r[5];
    NekDouble F = r[3] * r[6] + r[4] * r[7] + r[5] * r[8];
    NekDouble G = r[6] * r[6] + r[7] * r[7] + r[8] * r[8];
    NekDouble e = n[0] * r[9] + n[1] * r[10] + n[2] * r[11];
    NekDouble f = n[0] * r[15] + n[1] * r[16] + n[2] * r[17];
    NekDouble g = n[0] * r[12] + n[1] * r[13] + n[2] * r[14];

    // if det is zero cannot invert matrix, R=0 so must skip
    if (E * G - F * F < 1E-30)
    {
        return 0.0;
    }

    NekDouble K, H;

    K = (e * g - f * f) / (E * G - F * F);
    H = 0.5 * (e * G - 2 * f * F + g * E) / (E * G - F * F);

    NekDouble kv[2];
    kv[0] = abs(H + sqrt(H * H - K));
    kv[1] = abs(H - sqrt(H * H - K));

    return kv[0] > kv[1] ? kv[0] : kv[1];
}

Array< OneD, NekDouble > Nektar::NekMeshUtils::CADSurf::D1

(

Array< OneD, NekDouble >

uv

)

Get the set of first derivatives at parametric point u,v.

Parameters

uv	Array of u and v parametric coords.

Returns

Array of xyz copmonents of first derivatives.

Definition at line 282 of file CADSurf.cpp.

References m_occSurface, and Test().

{
    Test(uv);

    Array<OneD, NekDouble> r(9);
    gp_Pnt Loc;
    gp_Vec D1U, D1V;
    m_occSurface.D1(uv[0], uv[1], Loc, D1U, D1V);

    r[0] = Loc.X(); // x
    r[1] = Loc.Y(); // y
    r[2] = Loc.Z(); // z
    r[3] = D1U.X(); // dx/du
    r[4] = D1U.Y(); // dy/du
    r[5] = D1U.Z(); // dz/du
    r[6] = D1V.X(); // dx/dv
    r[7] = D1V.Y(); // dy/dv
    r[8] = D1V.Z(); // dz/dv

    return r;
}

Array< OneD, NekDouble > Nektar::NekMeshUtils::CADSurf::D2

(

Array< OneD, NekDouble >

uv

)

Get the set of second derivatives at parametric point u,v.

Parameters

uv	array of u and v parametric coords

Returns

array of xyz copmonents of second derivatives

Definition at line 304 of file CADSurf.cpp.

References m_occSurface, and Test().

Referenced by Curvature().

{
    Test(uv);

    Array<OneD, NekDouble> r(18);
    gp_Pnt Loc;
    gp_Vec D1U, D1V, D2U, D2V, D2UV;
    m_occSurface.D2(uv[0], uv[1], Loc, D1U, D1V, D2U, D2V, D2UV);

    r[0]  = Loc.X(); // x
    r[1]  = Loc.Y(); // y
    r[2]  = Loc.Z(); // z
    r[3]  = D1U.X(); // dx/dx
    r[4]  = D1U.Y(); // dy/dy
    r[5]  = D1U.Z(); // dz/dz
    r[6]  = D1V.X(); // dx/dx
    r[7]  = D1V.Y(); // dy/dy
    r[8]  = D1V.Z(); // dz/dz
    r[9]  = D2U.X(); // d2x/du2
    r[10] = D2U.Y(); // d2y/du2
    r[11] = D2U.Z(); // d2z/du2
    r[12] = D2V.X(); // d2x/dv2
    r[13] = D2V.Y(); // d2y/dv2
    r[14] = D2V.Z(); // d2z/dv2
    r[15] = D2UV.X(); // d2x/dudv
    r[16] = D2UV.Y(); // d2y/dudv
    r[17] = D2UV.Z(); // d2z/dudv

    return r;
}

NekDouble Nektar::NekMeshUtils::CADSurf::DistanceTo

(

Array< OneD, NekDouble >

p

)

does unconstrained locuv to project point from anywhere

Definition at line 185 of file CADSurf.cpp.

References m_occSurface.

{
    gp_Pnt loc(p[0] * 1000.0, p[1] * 1000.0, p[2] * 1000.0);

    // alternative locuv methods
    ShapeAnalysis_Surface sas(m_s);
    sas.SetDomain(m_occSurface.FirstUParameter(), m_occSurface.LastUParameter(),
                  m_occSurface.FirstVParameter(),
                  m_occSurface.LastVParameter());

    gp_Pnt2d p2 = sas.ValueOfUV(loc, 1e-7);

    gp_Pnt p3 = sas.Value(p2);

    return p3.Distance(loc);
}

Array<OneD, NekDouble> Nektar::NekMeshUtils::CADSurf::GetBounds ( )

inline

Get the limits of the parametric space for the surface.

Returns

Array of 4 entries with parametric umin,umax,vmin,vmax.

Definition at line 103 of file CADSurf.h.

References m_occSurface.

    {
        Array<OneD,NekDouble> b(4);

        b[0] = m_occSurface.FirstUParameter();
        b[1] = m_occSurface.LastUParameter();
        b[2] = m_occSurface.FirstVParameter();
        b[3] = m_occSurface.LastVParameter();

        return b;
    }

std::vector<EdgeLoop> Nektar::NekMeshUtils::CADSurf::GetEdges ( )

inline

Get the IDs of the edges which bound the surface.

The edges are organsised into two vectors, which are grouped into the continuous loops of the bounding edges, then the edges, which are a pair of integers. The first item is the edge ID and the second is an integer that indicates whether this edge is orientated forwards or backwards on this surface to form the loop.

Definition at line 93 of file CADSurf.h.

References m_edges.

    {
        return m_edges;
    }

bool Nektar::NekMeshUtils::CADSurf::GetTwoC ( )

inline

query two curves

Definition at line 186 of file CADSurf.h.

References m_hasTwoCurves.

{return m_hasTwoCurves;}

Nektar::NekMeshUtils::CADSurf::Handle ( Geom_Surface  )

private

Alternate OpenCascade object for surface. Used by reverse lookup.

bool Nektar::NekMeshUtils::CADSurf::IsPlane

(

)

returns true if the surface is flat (2D)

Definition at line 224 of file CADSurf.cpp.

References m_occSurface.

{
    if (m_occSurface.GetType() == GeomAbs_Plane)
    {
        return true;
    }
    else
    {
        return false;
    }
}

bool Nektar::NekMeshUtils::CADSurf::IsReversedNormal ( )

inline

Definition at line 170 of file CADSurf.h.

References m_correctNormal.

    {
        return !m_correctNormal;
    }

Array< OneD, NekDouble > Nektar::NekMeshUtils::CADSurf::locuv

(

Array< OneD, NekDouble >

p

)

Performs a reverse look up to find u,v and x,y,z.

Parameters

p	Array of xyz location

Returns

The parametric location of xyz on this surface

Definition at line 64 of file CADSurf.cpp.

References ASSERTL0, and m_occSurface.

{
    // has to transfer back to mm
    gp_Pnt loc(p[0] * 1000.0, p[1] * 1000.0, p[2] * 1000.0);

    GeomAPI_ProjectPointOnSurf projection(
        loc, m_s, m_occSurface.FirstUParameter(), m_occSurface.LastUParameter(),
        m_occSurface.FirstVParameter(), m_occSurface.LastVParameter(),
        Extrema_ExtAlgo_Tree);

    Array<OneD, NekDouble> uvr(2);
    if (projection.NbPoints() == 0)
    {
        // alternative locuv methods
        ShapeAnalysis_Surface sas(m_s);
        sas.SetDomain(
            m_occSurface.FirstUParameter(), m_occSurface.LastUParameter(),
            m_occSurface.FirstVParameter(), m_occSurface.LastVParameter());

        gp_Pnt2d p2 = sas.ValueOfUV(loc, 1e-7);
        uvr[0]      = p2.X();
        uvr[1]      = p2.Y();

        gp_Pnt p3 = sas.Value(p2);
        ASSERTL0(p3.Distance(loc) < 1e-3, "large locuv distance sas");
    }
    else
    {
        Quantity_Parameter ui;
        Quantity_Parameter vi;

        projection.Parameters(1, ui, vi);

        uvr[0] = ui;
        uvr[1] = vi;

        if (projection.Distance(1) > 1.0)
        {
            stringstream ss;
            cerr << "large locuv distance " << projection.Distance(1) / 1000.0
                 << endl;
        }
    }

    // if the uv returned is slightly off the surface
    //(which ShapeAnalysis_Surface can do sometimes)
    if (uvr[0] < m_occSurface.FirstUParameter() ||
        uvr[0] > m_occSurface.LastUParameter() ||
        uvr[1] < m_occSurface.FirstVParameter() ||
        uvr[1] > m_occSurface.LastVParameter())
    {
        if (uvr[0] < m_occSurface.FirstUParameter() &&
            fabs(m_occSurface.FirstUParameter() - uvr[0]) < 1E-6)
        {
            uvr[0] = m_occSurface.FirstUParameter();
        }
        else if (uvr[0] > m_occSurface.LastUParameter() &&
                 fabs(m_occSurface.LastUParameter() - uvr[0]) < 1E-6)
        {
            uvr[0] = m_occSurface.LastUParameter();
        }
        else if (uvr[1] < m_occSurface.FirstVParameter() &&
                 fabs(m_occSurface.FirstVParameter() - uvr[1]) < 1E-6)
        {
            uvr[1] = m_occSurface.FirstVParameter();
        }
        else if (uvr[1] > m_occSurface.LastVParameter() &&
                 fabs(m_occSurface.LastVParameter() - uvr[1]) < 1E-6)
        {
            uvr[1] = m_occSurface.LastVParameter();
        }
        else
        {
            ASSERTL0(false, "Cannot correct locuv");
        }
    }

    return uvr;
}

Array< OneD, NekDouble > Nektar::NekMeshUtils::CADSurf::N

(

Array< OneD, NekDouble >

uv

)

Get the normal vector at parametric point u,v.

Parameters

uv	Array of u and v parametric coords.

Returns

Array of xyz components of normal vector.

Definition at line 249 of file CADSurf.cpp.

References m_correctNormal, m_occSurface, and Test().

Referenced by Curvature().

{
    Test(uv);

    Array<OneD, NekDouble> normal(3);
    gp_Pnt Loc;
    gp_Vec D1U, D1V;
    m_occSurface.D1(uv[0], uv[1], Loc, D1U, D1V);
    gp_Vec n = D1U.Crossed(D1V);

    if (!m_correctNormal)
    {
        n.Reverse();
    }

    if (n.X() == 0 && n.Y() == 0 && n.Z() == 0)
    {
        // Return bad normal
        normal[0] = 0.0;
        normal[1] = 0.0;
        normal[2] = 0.0;
    }
    else
    {
        n.Normalize();
        normal[0] = n.X();
        normal[1] = n.Y();
        normal[2] = n.Z();
    }

    return normal;
}

Array< OneD, NekDouble > Nektar::NekMeshUtils::CADSurf::P

(

Array< OneD, NekDouble >

uv

)

Get the x,y,z at parametric point u,v.

Parameters

uv	Array of u and v parametric coords.

Returns

Array of xyz location.

Definition at line 236 of file CADSurf.cpp.

References m_occSurface, and Test().

{
    Test(uv);

    Array<OneD, NekDouble> location(3);
    gp_Pnt loc;
    loc         = m_occSurface.Value(uv[0], uv[1]);
    location[0] = loc.X();
    location[1] = loc.Y();
    location[2] = loc.Z();
    return location;
}

void Nektar::NekMeshUtils::CADSurf::ProjectTo	(	Array< OneD, NekDouble > &	tp,
		Array< OneD, NekDouble > &	uv
	)

Definition at line 202 of file CADSurf.cpp.

References m_occSurface.

{
    gp_Pnt loc(tp[0] * 1000.0, tp[1] * 1000.0, tp[2] * 1000.0);

    // alternative locuv methods
    ShapeAnalysis_Surface sas(m_s);
    sas.SetDomain(m_occSurface.FirstUParameter(), m_occSurface.LastUParameter(),
                  m_occSurface.FirstVParameter(),
                  m_occSurface.LastVParameter());

    gp_Pnt2d p2 = sas.ValueOfUV(loc, 1e-7);

    gp_Pnt p3 = sas.Value(p2);

    tp[0] = p3.X() / 1000.0;
    tp[1] = p3.Y() / 1000.0;
    tp[2] = p3.Z() / 1000.0;

    uv[0] = p2.X();
    uv[1] = p2.Y();
}

void Nektar::NekMeshUtils::CADSurf::SetReverseNomral ( )

inline

sets the flag to reverse the normal for this suface, this is determined in cadsystem and ensures all surface normals, point internaly

Definition at line 165 of file CADSurf.h.

References m_correctNormal.

    {
        m_correctNormal = false;
    }

void Nektar::NekMeshUtils::CADSurf::SetTwoC ( )

inline

surface needs to know if it is bounded by only two curves

Definition at line 178 of file CADSurf.h.

References m_hasTwoCurves.

    {
        m_hasTwoCurves = true;
    }

void Nektar::NekMeshUtils::CADSurf::Test ( Array< OneD, NekDouble >  uv )

private

Function which tests the the value of uv used is within the surface.

Definition at line 335 of file CADSurf.cpp.

References ASSERTL0, Nektar::NekMeshUtils::CADObj::GetId(), and m_occSurface.

Referenced by Curvature(), D1(), D2(), N(), and P().

{
    stringstream error;

    error << "Point not within parameter plane: ";

    bool passed = true;

    if (uv[0] < m_occSurface.FirstUParameter())
    {
        if (fabs(uv[0] - m_occSurface.FirstUParameter()) > 1E-8)
        {
            error << "U(" << uv[0] << ") is less than Umin("
                  << m_occSurface.FirstUParameter() << ")";
            passed = false;
        }
    }
    else if (uv[0] > m_occSurface.LastUParameter())
    {
        if (fabs(uv[0] - m_occSurface.LastUParameter()) > 1E-8)
        {
            error << "U(" << uv[0] << ") is greater than Umax("
                  << m_occSurface.LastUParameter() << ")";
            passed = false;
        }
    }
    else if (uv[1] < m_occSurface.FirstVParameter())
    {
        if (fabs(uv[1] - m_occSurface.FirstVParameter()) > 1E-8)
        {
            error << "V(" << uv[1] << ") is less than Vmin("
                  << m_occSurface.FirstVParameter() << ")";
            passed = false;
        }
    }
    else if (uv[1] > m_occSurface.LastVParameter())
    {
        if (fabs(uv[1] - m_occSurface.LastVParameter()) > 1E-8)
        {
            error << "V(" << uv[1] << ") is greater than Vmax("
                  << m_occSurface.LastVParameter() << ")";
            passed = false;
        }
    }

    error << " On Surface: " << GetId();

    ASSERTL0(passed, error.str());
}

Friends And Related Function Documentation

friend class MemoryManager< CADSurf >

friend

Definition at line 75 of file CADSurf.h.

Member Data Documentation

bool Nektar::NekMeshUtils::CADSurf::m_correctNormal

private

normal

Definition at line 205 of file CADSurf.h.

Referenced by CADSurf(), IsReversedNormal(), N(), and SetReverseNomral().

std::vector<EdgeLoop> Nektar::NekMeshUtils::CADSurf::m_edges

private

List of bounding edges in loops with orientation.

Definition at line 214 of file CADSurf.h.

Referenced by GetEdges().

bool Nektar::NekMeshUtils::CADSurf::m_hasTwoCurves

private

flag to alert the mesh generation to a potential problem is both curves have only two points in the mesh

Definition at line 208 of file CADSurf.h.

Referenced by CADSurf(), GetTwoC(), and SetTwoC().

BRepAdaptor_Surface Nektar::NekMeshUtils::CADSurf::m_occSurface

private

OpenCascade object for surface.

Definition at line 210 of file CADSurf.h.

Referenced by CADSurf(), D1(), D2(), DistanceTo(), GetBounds(), IsPlane(), locuv(), N(), P(), ProjectTo(), and Test().