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Adding size control arguments to collapseFaceToEdge and tweaking.

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Adding collapseFaces function to filter faces in the whole mesh using
collapseFaceToEdge.
This commit is contained in:
graham
2010-01-05 18:02:16 +00:00
parent 2c52371be1
commit 0a0992b9ed
3 changed files with 398 additions and 213 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
src/mesh/conformalVoronoiMesh/conformalVoronoiMesh/conformalVoronoiMesh.H
View File

@ -508,7 +508,9 @@ private:
( (
const face& f, const face& f,
pointField& pts, pointField& pts,
Map<label>& dualPtIndexMap Map<label>& dualPtIndexMap,
scalar targetFaceSize,
scalar collapseSizeLimitCoeff
) const; ) const;
//- Re-index all of the the Delaunay cells //- Re-index all of the the Delaunay cells

605
src/mesh/conformalVoronoiMesh/conformalVoronoiMesh/conformalVoronoiMeshCalcDualMesh.C
View File

@ -349,7 +349,10 @@ void Foam::conformalVoronoiMesh::calcDualMesh
smoothSurface(points); smoothSurface(points);
// Collapse faces throughout the mesh // Collapse faces throughout the mesh
// collapseFaces(points);
Info<< nl << " Collapsing unnecessary faces" << endl;
collapseFaces(points);
// Final dual face and owner neighbour construction // Final dual face and owner neighbour construction
@ -783,7 +786,7 @@ Foam::label Foam::conformalVoronoiMesh::smoothSurfaceDualFaces
Cell_handle c = eit->first; Cell_handle c = eit->first;
Vertex_handle vA = c->vertex(eit->second); Vertex_handle vA = c->vertex(eit->second);
// Vertex_handle vB = c->vertex(eit->third); Vertex_handle vB = c->vertex(eit->third);
if (!vA->internalOrBoundaryPoint()) if (!vA->internalOrBoundaryPoint())
{ {
@ -796,7 +799,23 @@ Foam::label Foam::conformalVoronoiMesh::smoothSurfaceDualFaces
if ((faceNormal & surfaceNormal) < cosPerpendicularToleranceAngle) if ((faceNormal & surfaceNormal) < cosPerpendicularToleranceAngle)
{ {
if (collapseFaceToEdge(dualFace, pts, dualPtIndexMap)) scalar targetFaceSize = averageAnyCellSize(vA, vB);
// Selecting faces to collapse based on angle to
// surface, so set collapseSizeLimitCoeff to GREAT to
// allow collapse of all faces
if
(
collapseFaceToEdge
(
dualFace,
pts,
dualPtIndexMap,
targetFaceSize,
GREAT
)
)
{ {
nCollapsedFaces++; nCollapsedFaces++;
} }
@ -810,10 +829,6 @@ Foam::label Foam::conformalVoronoiMesh::smoothSurfaceDualFaces
void Foam::conformalVoronoiMesh::collapseFaces(pointField& pts) void Foam::conformalVoronoiMesh::collapseFaces(pointField& pts)
{ {
// Assess faces for collapse
Info<< nl << " Collapsing unnecessary faces" << endl;
label nCollapsedFaces = 0; label nCollapsedFaces = 0;
do do
@ -824,7 +839,12 @@ void Foam::conformalVoronoiMesh::collapseFaces(pointField& pts)
reindexDualVertices(dualPtIndexMap); reindexDualVertices(dualPtIndexMap);
Info<< " Collapsed " << nCollapsedFaces << " faces" << endl; mergeCloseDualVertices(pts);
if (nCollapsedFaces > 0)
{
Info<< " Collapsed " << nCollapsedFaces << " faces" << endl;
}
} while (nCollapsedFaces > 0); } while (nCollapsedFaces > 0);
} }
@ -838,10 +858,7 @@ Foam::label Foam::conformalVoronoiMesh::collapseFaces
{ {
label nCollapsedFaces = 0; label nCollapsedFaces = 0;
scalar smallEdgeLengthCoeff = 1e-3; scalar collapseSizeLimitCoeff = 0.2;
scalar smallFaceAreaCoeff = sqr(smallEdgeLengthCoeff);
scalar collapseToEdgeCoeff = 0.02;
scalar longestEdgeLengthRatio = 0.35;
for for
( (
@ -882,192 +899,259 @@ Foam::label Foam::conformalVoronoiMesh::collapseFaces
continue; continue;
} }
scalar area = dualFace.mag(pts);
scalar targetFaceSize = averageAnyCellSize(vA, vB); scalar targetFaceSize = averageAnyCellSize(vA, vB);
scalar targetArea = sqr(targetFaceSize);
if (area < smallFaceAreaCoeff*targetArea) if
(
collapseFaceToEdge
(
dualFace,
pts,
dualPtIndexMap,
targetFaceSize,
collapseSizeLimitCoeff
)
)
{ {
// Collapse the dual face nCollapsedFaces++;
// Determine if the face should be collapsed to a line or a
// point
const edgeList& eds = dualFace.edges();
label longestEdgeI = -1;
scalar longestEdgeLength = -SMALL;
scalar perimeter = 0.0;
forAll(eds, edI)
{
scalar edgeLength = eds[edI].mag(pts);
perimeter += edgeLength;
if (edgeLength > longestEdgeLength)
{
longestEdgeI = edI;
longestEdgeLength = edgeLength;
}
}
if
(
longestEdgeLength > collapseToEdgeCoeff*targetFaceSize
&& longestEdgeLength/perimeter > longestEdgeLengthRatio
)
{
// Collapse to edge
// Start at either end of the longest edge and consume the
// rest of the points of the face
const edge& longestEd = eds[longestEdgeI];
label longestEdStartPtI = longestEd.start();
label longestEdEndPtI = longestEd.end();
label revEdI = longestEdgeI;
label fwdEdI = longestEdgeI;
point revPt = pts[longestEdStartPtI];
point fwdPt = pts[longestEdEndPtI];
dualPtIndexMap.insert(longestEdStartPtI, longestEdStartPtI);
dualPtIndexMap.insert(longestEdEndPtI, longestEdEndPtI);
for (label fcI = 1; fcI <= label(eds.size()/2); fcI++)
{
revEdI = eds.rcIndex(revEdI);
fwdEdI = eds.fcIndex(fwdEdI);
const edge& revEd = eds[revEdI];
const edge& fwdEd = eds[fwdEdI];
if (fcI < label(eds.size()/2))
{
revPt += pts[revEd.start()];
fwdPt += pts[fwdEd.end()];
dualPtIndexMap.insert
(
revEd.start(),
longestEdStartPtI
);
dualPtIndexMap.insert
(
fwdEd.end(),
longestEdEndPtI
);
}
else
{
// Final circulation
if
(
eds.size() % 2 == 1
&& revEd.start() == fwdEd.end()
)
{
// Odd number of edges, give final point to
// the edge direction that has the shorter
// final edge
if (fwdEd.mag(pts) < revEd.mag(pts))
{
fwdPt += pts[fwdEd.end()];
dualPtIndexMap.insert
(
fwdEd.end(),
longestEdEndPtI
);
revPt /= fcI;
fwdPt /= (fcI + 1);
}
else
{
revPt += pts[revEd.start()];
dualPtIndexMap.insert
(
revEd.start(),
longestEdStartPtI
);
revPt /= (fcI + 1);
fwdPt /= fcI;
}
}
else if
(
eds.size() % 2 == 0
&& revEd.start() == fwdEd.start()
&& revEd.end() == fwdEd.end()
)
{
// Even number of edges
revPt /= fcI;
fwdPt /= fcI;
}
else
{
FatalErrorIn
(
"Foam::conformalVoronoiMesh::collapseFace"
)
<< "Face circulation failed for face "
<< dualFace << nl
<< exit(FatalError);
}
}
}
// Move the position of the accumulated points
pts[longestEdStartPtI] = revPt;
pts[longestEdEndPtI] = fwdPt;
nCollapsedFaces++;
}
else if
(
longestEdgeLength <= collapseToEdgeCoeff*targetFaceSize
)
{
// Collapse to point
point resultantPt = vector::zero;
label collapseToPtI = dualFace[0];
forAll(dualFace, fPtI)
{
label ptI = dualFace[fPtI];
resultantPt += pts[ptI];
dualPtIndexMap.insert(ptI, collapseToPtI);
}
resultantPt /= dualFace.size();
pts[collapseToPtI] = resultantPt;
nCollapsedFaces++;
}
} }
} }
} }
// ------> OLD, FOR REFERENCE
// scalar smallEdgeLengthCoeff = 1e-3;
// scalar smallFaceAreaCoeff = sqr(smallEdgeLengthCoeff);
// scalar collapseToEdgeCoeff = 0.02;
// scalar longestEdgeLengthRatio = 0.35;
// for
// (
// Triangulation::Finite_edges_iterator eit = finite_edges_begin();
// eit != finite_edges_end();
// ++eit
// )
// {
// Cell_circulator ccStart = incident_cells(*eit);
// Cell_circulator cc = ccStart;
// do
// {
// if (dualPtIndexMap.found(cc->cellIndex()))
// {
// // One of the points of this face has already been
// // collapsed this sweep, leave for next sweep
// continue;
// }
// } while (++cc != ccStart);
// Cell_handle c = eit->first;
// Vertex_handle vA = c->vertex(eit->second);
// Vertex_handle vB = c->vertex(eit->third);
// if
// (
// vA->internalOrBoundaryPoint()
// || vB->internalOrBoundaryPoint()
// )
// {
// face dualFace = buildDualFace(eit);
// if (dualFace.size() < 3)
// {
// // This face has been collapsed already
// continue;
// }
// scalar area = dualFace.mag(pts);
// scalar targetFaceSize = averageAnyCellSize(vA, vB);
// scalar targetArea = sqr(targetFaceSize);
// if (area < smallFaceAreaCoeff*targetArea)
// {
// // Collapse the dual face
// // Determine if the face should be collapsed to a line or a
// // point
// const edgeList& eds = dualFace.edges();
// label longestEdgeI = -1;
// scalar longestEdgeLength = -SMALL;
// scalar perimeter = 0.0;
// forAll(eds, edI)
// {
// scalar edgeLength = eds[edI].mag(pts);
// perimeter += edgeLength;
// if (edgeLength > longestEdgeLength)
// {
// longestEdgeI = edI;
// longestEdgeLength = edgeLength;
// }
// }
// if
// (
// longestEdgeLength > collapseToEdgeCoeff*targetFaceSize
// && longestEdgeLength/perimeter > longestEdgeLengthRatio
// )
// {
// // Collapse to edge
// // Start at either end of the longest edge and consume the
// // rest of the points of the face
// const edge& longestEd = eds[longestEdgeI];
// label longestEdStartPtI = longestEd.start();
// label longestEdEndPtI = longestEd.end();
// label revEdI = longestEdgeI;
// label fwdEdI = longestEdgeI;
// point revPt = pts[longestEdStartPtI];
// point fwdPt = pts[longestEdEndPtI];
// dualPtIndexMap.insert(longestEdStartPtI, longestEdStartPtI);
// dualPtIndexMap.insert(longestEdEndPtI, longestEdEndPtI);
// for (label fcI = 1; fcI <= label(eds.size()/2); fcI++)
// {
// revEdI = eds.rcIndex(revEdI);
// fwdEdI = eds.fcIndex(fwdEdI);
// const edge& revEd = eds[revEdI];
// const edge& fwdEd = eds[fwdEdI];
// if (fcI < label(eds.size()/2))
// {
// revPt += pts[revEd.start()];
// fwdPt += pts[fwdEd.end()];
// dualPtIndexMap.insert
// (
// revEd.start(),
// longestEdStartPtI
// );
// dualPtIndexMap.insert
// (
// fwdEd.end(),
// longestEdEndPtI
// );
// }
// else
// {
// // Final circulation
// if
// (
// eds.size() % 2 == 1
// && revEd.start() == fwdEd.end()
// )
// {
// // Odd number of edges, give final point to
// // the edge direction that has the shorter
// // final edge
// if (fwdEd.mag(pts) < revEd.mag(pts))
// {
// fwdPt += pts[fwdEd.end()];
// dualPtIndexMap.insert
// (
// fwdEd.end(),
// longestEdEndPtI
// );
// revPt /= fcI;
// fwdPt /= (fcI + 1);
// }
// else
// {
// revPt += pts[revEd.start()];
// dualPtIndexMap.insert
// (
// revEd.start(),
// longestEdStartPtI
// );
// revPt /= (fcI + 1);
// fwdPt /= fcI;
// }
// }
// else if
// (
// eds.size() % 2 == 0
// && revEd.start() == fwdEd.start()
// && revEd.end() == fwdEd.end()
// )
// {
// // Even number of edges
// revPt /= fcI;
// fwdPt /= fcI;
// }
// else
// {
// FatalErrorIn
// (
// "Foam::conformalVoronoiMesh::collapseFace"
// )
// << "Face circulation failed for face "
// << dualFace << nl
// << exit(FatalError);
// }
// }
// }
// // Move the position of the accumulated points
// pts[longestEdStartPtI] = revPt;
// pts[longestEdEndPtI] = fwdPt;
// nCollapsedFaces++;
// }
// else if
// (
// longestEdgeLength <= collapseToEdgeCoeff*targetFaceSize
// )
// {
// // Collapse to point
// point resultantPt = vector::zero;
// label collapseToPtI = dualFace[0];
// forAll(dualFace, fPtI)
// {
// label ptI = dualFace[fPtI];
// resultantPt += pts[ptI];
// dualPtIndexMap.insert(ptI, collapseToPtI);
// }
// resultantPt /= dualFace.size();
// pts[collapseToPtI] = resultantPt;
// nCollapsedFaces++;
// }
// }
// }
// }
// <------ OLD, FOR REFERENCE
return nCollapsedFaces; return nCollapsedFaces;
} }
@ -1076,18 +1160,19 @@ bool Foam::conformalVoronoiMesh::collapseFaceToEdge
( (
const face& f, const face& f,
pointField& pts, pointField& pts,
Map<label>& dualPtIndexMap Map<label>& dualPtIndexMap,
scalar targetFaceSize,
scalar collapseSizeLimitCoeff
) const ) const
{ {
scalar guardFraction = 0.3;
const vector fC = f.centre(pts); const vector fC = f.centre(pts);
vector fN = f.normal(pts); vector fN = f.normal(pts);
const scalar fA = mag(fN); const scalar fA = mag(fN);
// Face normal is now a unit vector
fN /= fA;
tensor J = f.inertia(pts, fC); tensor J = f.inertia(pts, fC);
// Find the dominant collapse direction by finding the eigenvector // Find the dominant collapse direction by finding the eigenvector
@ -1097,9 +1182,47 @@ bool Foam::conformalVoronoiMesh::collapseFaceToEdge
// Normalise inertia tensor to remove problems with small values // Normalise inertia tensor to remove problems with small values
J /= mag(J); scalar magJ = mag(J);
// J /= cmptMax(J);
// J /= max(eigenValues(J).x(), SMALL); if (magJ > VSMALL)
{
J /= mag(J);
// J /= cmptMax(J);
// J /= max(eigenValues(J).x(), SMALL);
}
else
{
WarningIn
(
"Foam::conformalVoronoiMesh::collapseFaceToEdge"
"("
"const face& f,"
"pointField& pts,"
"Map<label>& dualPtIndexMap"
") const"
)
<< "Inertia tensor magnitude too small, not collapsing." << nl
<< J << nl << "mag = " << magJ
<< endl;
// Output face for visualisation
forAll(f, fPtI)
{
meshTools::writeOBJ(Info, pts[f[fPtI]]);
}
Info<< "f";
forAll(f, fPtI)
{
Info << " " << fPtI + 1;
}
Info<< nl << endl;
return false;
}
vector eVals = eigenValues(J); vector eVals = eigenValues(J);
@ -1110,6 +1233,9 @@ bool Foam::conformalVoronoiMesh::collapseFaceToEdge
// These assumption can be tested with the code below; they are // These assumption can be tested with the code below; they are
// only likely to be invalid for very warped faces. // only likely to be invalid for very warped faces.
// // Face normal is now a unit vector
// fN /= fA;
// direction normalMatchEigenValueCmpt = -1; // direction normalMatchEigenValueCmpt = -1;
// scalar normalMatchMaxMagDotProd = -SMALL; // scalar normalMatchMaxMagDotProd = -SMALL;
@ -1324,7 +1450,56 @@ bool Foam::conformalVoronoiMesh::collapseFaceToEdge
// guardFraction (g) of the distance form the face centre to the // guardFraction (g) of the distance form the face centre to the
// furthest vertex in the considered direction // furthest vertex in the considered direction
scalar guardFraction = 0.8; if (dNeg.size() == 0 || dPos.size() == 0)
{
WarningIn
(
"Foam::conformalVoronoiMesh::collapseFaceToEdge"
"("
"const face& f,"
"pointField& pts,"
"Map<label>& dualPtIndexMap"
") const"
)
<< "All points on one side of face centre, not collapsing."
<< endl;
// Output face and collapse axis for visualisation
Info<< nl << "# Aspect ratio = " << aspectRatio << nl
<< "# collapseAxis = " << collapseAxis << nl
<< "# eigenvalues = " << eVals << endl;
scalar scale = 2.0*mag(fC - pts[f[0]]);
meshTools::writeOBJ(Info, fC);
meshTools::writeOBJ(Info, fC + scale*collapseAxis);
Info<< "f 1 2" << endl;
forAll(f, fPtI)
{
meshTools::writeOBJ(Info, pts[f[fPtI]]);
}
Info<< "f";
forAll(f, fPtI)
{
Info << " " << fPtI + 3;
}
Info<< nl << "# " << d << endl;
Info<< "# " << d.first() << " " << d.last() << endl;
forAll(d, dI)
{
meshTools::writeOBJ(Info, fC + d[dI]*collapseAxis);
}
return false;
}
bool validCollapse = false; bool validCollapse = false;
@ -1332,6 +1507,8 @@ bool Foam::conformalVoronoiMesh::collapseFaceToEdge
( (
(dNeg.last() < guardFraction*dNeg.first()) (dNeg.last() < guardFraction*dNeg.first())
&& (dPos.first() > guardFraction*dPos.last()) && (dPos.first() > guardFraction*dPos.last())
&& (fA < aspectRatio*sqr(targetFaceSize*collapseSizeLimitCoeff))
&& f.size() <= 4
) )
{ {
validCollapse = true; validCollapse = true;
@ -1339,7 +1516,6 @@ bool Foam::conformalVoronoiMesh::collapseFaceToEdge
if (validCollapse) if (validCollapse)
{ {
// Arbitrarily choosing the most distant point as the index to // Arbitrarily choosing the most distant point as the index to
// collapse to. // collapse to.
@ -1366,20 +1542,27 @@ bool Foam::conformalVoronoiMesh::collapseFaceToEdge
// If the face can't be collapsed to a line, and it is small // If the face can't be collapsed to a line, and it is small
// and low aspect ratio enough, collapse it to a point. // and low aspect ratio enough, collapse it to a point.
// if (aspectRatio < 2.0) if
// { (
// // Arbitrarily choosing the first point as the index to (d.last() - d.first()) < targetFaceSize*0.35
// // collapse to. Collapse to the face center. && fA < aspectRatio*sqr(targetFaceSize*collapseSizeLimitCoeff)
&& f.size() <= 4
)
{
// Arbitrarily choosing the first point as the index to
// collapse to. Collapse to the face center.
// label collapseToPtI = facePts.first(); label collapseToPtI = facePts.first();
// forAll(facePts, fPtI) forAll(facePts, fPtI)
// { {
// dualPtIndexMap.insert(facePts[fPtI], collapseToPtI); dualPtIndexMap.insert(facePts[fPtI], collapseToPtI);
// } }
// pts[collapseToPtI] = fC; pts[collapseToPtI] = fC;
// }
validCollapse = true;
}
// Alternatively, do not topologically collapse face, but push // Alternatively, do not topologically collapse face, but push
// all points onto a line, so that the face area is zero and // all points onto a line, so that the face area is zero and

2
src/mesh/conformalVoronoiMesh/conformalVoronoiMesh/conformalVoronoiMeshI.H
View File

@ -85,7 +85,7 @@ inline Foam::scalar Foam::conformalVoronoiMesh::averageAnyCellSize
"const Vertex_handle& vB" "const Vertex_handle& vB"
") const" ") const"
) )
<< "Requested averageCellSize for to external points" << "Requested averageCellSize for two external points"
<< nl << nl
<< exit(FatalError); << exit(FatalError);
} }