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OCC better divide edge algorithm

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Hochsteger, Matthias 2023-02-13 15:57:53 +01:00 committed by Schöberl, Joachim
parent 9eb959f608
commit 219c2af686
7 changed files with 106 additions and 92 deletions
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75
libsrc/meshing/basegeom.cpp
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@ -479,50 +479,71 @@ namespace netgen
mesh.LoadLocalMeshSize(mparam.meshsizefilename);
}
void DivideEdge(GeometryEdge * edge, const MeshingParameters & mparam, const Mesh & mesh, Array<Point<3>> & points, Array<double> & params, int layer)
void GeometryEdge :: Divide(const MeshingParameters & mparam, const Mesh & mesh, Array<Point<3>> & points, Array<double> & params)
{
static Timer tdivedgesections("Divide edge sections");
static Timer tdivide("Divide Edges");
RegionTimer rt(tdivide);
// -------------------- DivideEdge -----------------
static constexpr size_t divide_edge_sections = 10000;
double hvalue[divide_edge_sections+1];
hvalue[0] = 0;
Point<3> old_pt = edge->GetPoint(0.);
// calc local h for edge
tdivedgesections.Start();
for(auto i : Range(divide_edge_sections))
{
auto pt = edge->GetPoint(double(i+1)/divide_edge_sections);
hvalue[i+1] = hvalue[i] + 1./mesh.GetH(pt, layer) * (pt-old_pt).Length();
old_pt = pt;
auto layer = properties.layer;
double safety = 0.5*(1.-mparam.grading);
double lam = 0.0;
Point<3> p = GetPoint(0.0);
auto old_p = p;
Array<double> hvalue, fine_params;
hvalue.Append(.0);
while (lam<1. && hvalue.Size() < 20000) {
fine_params.Append(lam);
auto h = mesh.GetH(old_p, layer);
auto step = safety * h/GetTangent(lam).Length();
lam += step;
lam = min2(lam, 1.0);
p = GetPoint(lam);
hvalue.Append((hvalue.Size()==0 ? 0.0 : hvalue.Last()) + 1./h * (p-old_p).Length());
old_p = p;
}
int nsubedges = max2(1, int(floor(hvalue[divide_edge_sections]+0.5)));
fine_params.Append(1.0);
if(hvalue.Size()==20000 && lam<1.0)
cout << "Warning: Could not divide Edge" << endl;
tdivedgesections.Stop();
auto n = hvalue.Size()-1;
int nsubedges = max2(1, int(floor(hvalue.Last()+0.5)));
points.SetSize(nsubedges-1);
params.SetSize(nsubedges+1);
int i = 1;
int i1 = 0;
do
for(auto i : Range(1,nsubedges))
{
if (hvalue[i1]/hvalue[divide_edge_sections]*nsubedges >= i)
{
params[i] = (double(i1)/divide_edge_sections);
points[i-1] = MeshPoint(edge->GetPoint(params[i]));
i++;
}
auto h_target = i*hvalue.Last()/nsubedges;
while(hvalue[i1]<h_target && i1<hvalue.Size())
i1++;
if (i1 > divide_edge_sections)
if(i1==hvalue.Size())
{
nsubedges = i;
points.SetSize(nsubedges-1);
params.SetSize(nsubedges+1);
points.SetSize(i-1);
params.SetSize(i+1);
cout << "divide edge: local h too small" << endl;
break;
}
} while(i < nsubedges);
// interpolate lam between points
auto lam0 = fine_params[i1-1];
auto lam1 = fine_params[i1];
auto h0 = hvalue[i1-1];
auto h1 = hvalue[i1];
auto fac = (h_target-h0)/(h1-h0);
auto lam = lam0 + fac*(lam1-lam0);
params[i] = lam;
points[i-1] = MeshPoint(GetPoint(params[i]));
}
params[0] = 0.;
params[nsubedges] = 1.;
@ -616,7 +637,7 @@ namespace netgen
}
else
{
DivideEdge(edge, mparam, mesh, edge_points, params, edge->properties.layer);
edge->Divide(mparam, mesh, edge_points, params);
}
}
else

1
libsrc/meshing/basegeom.hpp
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@ -110,6 +110,7 @@ namespace netgen
}
virtual Vec<3> GetTangent(double t) const = 0;
virtual bool IsMappedShape( const GeometryShape & other, const Transformation<3> & trafo, double tolerance ) const override;
virtual void Divide(const MeshingParameters & mparam, const Mesh & mesh, Array<Point<3>> & points, Array<double> & params);
};
class DLL_HEADER GeometryFace : public GeometryShape

3
libsrc/occ/occ_edge.cpp
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@ -69,6 +69,7 @@ namespace netgen
gp_Pnt p;
gp_Vec v;
curve->D1(t, p, v);
return occ2ng(v);
return occ2ng(v) * (s1-s0);
}
}

18
libsrc/occ/occ_face.cpp
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@ -1,6 +1,7 @@
#include <BRepGProp.hxx>
#include <BRep_Tool.hxx>
#include <GeomAPI_ProjectPointOnCurve.hxx>
#include <BRepLProp_SLProps.hxx>
#include "occ_edge.hpp"
#include "occ_face.hpp"
@ -111,9 +112,16 @@ namespace netgen
for(auto i : Range(2))
{
// take uv from CurveOnSurface as start value but project again for better accuracy
// (cof->Value yields wrong values (outside of surface) for complicated faces
auto uv = cof->Value(s[i]);
seg.epgeominfo[i].u = uv.X();
seg.epgeominfo[i].v = uv.Y();
PointGeomInfo gi;
gi.u = uv.X();
gi.v = uv.Y();
Point<3> pproject = mesh[seg[i]];
ProjectPointGI(pproject, gi);
seg.epgeominfo[i].u = gi.u;
seg.epgeominfo[i].v = gi.v;
}
bool do_swap = ORIENTATION == REVERSED;
@ -234,7 +242,11 @@ namespace netgen
double OCCFace::GetCurvature(const PointGeomInfo& gi) const
{
throw Exception(ToString("not implemented") + __FILE__ + ":" + ToString(__LINE__));
BRepAdaptor_Surface sf(face, Standard_True);
BRepLProp_SLProps prop2(sf, 2, 1e-5);
prop2.SetParameters (gi.u, gi.v);
return max(fabs(prop2.MinCurvature()),
fabs(prop2.MaxCurvature()));
}
void OCCFace::RestrictH(Mesh& mesh, const MeshingParameters& mparam) const

15
libsrc/occ/occ_utils.hpp
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@ -276,8 +276,7 @@ namespace netgen
}
};
inline gp_Pnt Center (TopoDS_Shape shape)
inline auto Properties (TopoDS_Shape shape)
{
GProp_GProps props;
double tol;
@ -299,7 +298,17 @@ namespace netgen
default:
BRepGProp::LinearProperties(shape, props);
}
return props.CentreOfMass();
return props;
}
inline gp_Pnt Center (TopoDS_Shape shape)
{
return Properties(shape).CentreOfMass();
}
inline double Mass (TopoDS_Shape shape)
{
return Properties(shape).Mass();
}
}

6
libsrc/occ/occgenmesh.cpp
View File

@ -537,9 +537,7 @@ namespace netgen
multithread.percent = 100 * (i-1)/double(nedges);
if (BRep_Tool::Degenerated(e)) continue;
GProp_GProps system;
BRepGProp::LinearProperties(e, system);
double len = system.Mass();
double len = Mass(e);
if (len < mincurvelength)
{
@ -587,7 +585,7 @@ namespace netgen
localh = min2(localh, OCCGeometry::GetProperties(e).maxh);
maxedgelen = max (maxedgelen, len);
minedgelen = min (minedgelen, len);
int maxj = max((int) ceil(len/localh), 2);
int maxj = max((int) ceil(len/localh)*2, 2);
for (int j = 0; j <= maxj; j++)
{

34
libsrc/occ/python_occ_shapes.cpp
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@ -715,23 +715,8 @@ DLL_HEADER void ExportNgOCCShapes(py::module &m)
.def("Properties", [] (const TopoDS_Shape & shape)
{
GProp_GProps props;
switch (shape.ShapeType())
{
case TopAbs_FACE:
case TopAbs_SHELL:
BRepGProp::SurfaceProperties (shape, props); break;
case TopAbs_SOLID:
case TopAbs_COMPOUND:
case TopAbs_COMPSOLID:
BRepGProp::VolumeProperties (shape, props); break;
default:
BRepGProp::LinearProperties(shape, props);
// throw Exception("Properties implemented only for FACE");
}
double mass = props.Mass();
gp_Pnt center = props.CentreOfMass();
return tuple( py::cast(mass), py::cast(center) );
auto props = Properties(shape);
return tuple( py::cast(props.Mass()), py::cast(props.CentreOfMass()) );
}, "returns tuple of shape properties, currently ('mass', 'center'")
.def_property_readonly("center", [](const TopoDS_Shape & shape) {
@ -739,20 +724,7 @@ DLL_HEADER void ExportNgOCCShapes(py::module &m)
}, "returns center of gravity of shape")
.def_property_readonly("mass", [](const TopoDS_Shape & shape) {
GProp_GProps props;
switch (shape.ShapeType())
{
case TopAbs_FACE:
case TopAbs_SHELL:
BRepGProp::SurfaceProperties (shape, props); break;
case TopAbs_SOLID:
case TopAbs_COMPOUND:
case TopAbs_COMPSOLID:
BRepGProp::VolumeProperties (shape, props); break;
default:
BRepGProp::LinearProperties(shape, props);
}
return props.Mass();
return Mass(shape);
}, "returns mass of shape, what is length, face, or volume")
.def("Move", [](const TopoDS_Shape & shape, const gp_Vec v)