void Foam::momentOfInertia::massPropertiesShell
(
const pointField& pts,
const triFaceList& triFaces,
scalar density,
scalar& mass,
vector& cM,
tensor& J
)
{
// Reset properties for accumulation
mass = 0.0;
cM = vector::zero;
J = tensor::zero;
// Find centre of mass
forAll(triFaces, i)
{
const triFace& tri(triFaces[i]);
triPointRef t
(
pts[tri[0]],
pts[tri[1]],
pts[tri[2]]
);
scalar triMag = t.mag();
cM += triMag*t.centre();
mass += triMag;
}
cM /= mass;
mass *= density;
// Find inertia around centre of mass
forAll(triFaces, i)
{
const triFace& tri(triFaces[i]);
J += triPointRef
(
pts[tri[0]],
pts[tri[1]],
pts[tri[2]]
).inertia(cM, density);
}
}
Foam::pointHit Foam::face::fastIntersection
(
const point& p,
const vector& q,
const point& ctr,
const pointField& meshPoints,
const intersection::algorithm alg,
const scalar tol
) const
{
scalar nearestHitDist = VGREAT;
// Initialize to miss, distance = GREAT
pointHit nearest(p);
const labelList& f = *this;
forAll(f, pI)
{
// Note: for best accuracy, centre point always comes last
pointHit curHit = triPointRef
(
meshPoints[f[pI]],
meshPoints[f[fcIndex(pI)]],
ctr
).fastIntersection(p, q, alg, tol);
if (curHit.hit())
{
if (Foam::mag(curHit.distance()) < nearestHitDist)
{
nearestHitDist = Foam::mag(curHit.distance());
nearest.setHit();
nearest.setPoint(curHit.hitPoint());
}
}
}
Foam::pointHit Foam::tetrahedron<Point, PointRef>::containmentSphere
(
const scalar tol
) const
{
// (Probably very inefficient) minimum containment sphere calculation.
// From http://www.imr.sandia.gov/papers/imr11/shewchuk2.pdf:
// Sphere ctr is smallest one of
// - tet circumcentre
// - triangle circumcentre
// - edge mids
const scalar fac = 1 + tol;
// Halve order of tolerance for comparisons of sqr.
const scalar facSqr = Foam::sqrt(fac);
// 1. Circumcentre itself.
pointHit pHit(circumCentre());
pHit.setHit();
scalar minRadiusSqr = magSqr(pHit.rawPoint() - a_);
// 2. Try circumcentre of tet triangles. Create circumcircle for triFace and
// check if 4th point is inside.
{
point ctr = triPointRef(a_, b_, c_).circumCentre();
scalar radiusSqr = magSqr(ctr - a_);
if
(
radiusSqr < minRadiusSqr
&& Foam::magSqr(d_-ctr) <= facSqr*radiusSqr
)
{
pHit.setMiss(false);
pHit.setPoint(ctr);
minRadiusSqr = radiusSqr;
}
}
{
point ctr = triPointRef(a_, b_, d_).circumCentre();
scalar radiusSqr = magSqr(ctr - a_);
if
(
radiusSqr < minRadiusSqr
&& Foam::magSqr(c_-ctr) <= facSqr*radiusSqr
)
{
pHit.setMiss(false);
pHit.setPoint(ctr);
minRadiusSqr = radiusSqr;
}
}
{
point ctr = triPointRef(a_, c_, d_).circumCentre();
scalar radiusSqr = magSqr(ctr - a_);
if
(
radiusSqr < minRadiusSqr
&& Foam::magSqr(b_-ctr) <= facSqr*radiusSqr
)
{
pHit.setMiss(false);
pHit.setPoint(ctr);
minRadiusSqr = radiusSqr;
}
}
{
point ctr = triPointRef(b_, c_, d_).circumCentre();
scalar radiusSqr = magSqr(ctr - b_);
if
(
radiusSqr < minRadiusSqr
&& Foam::magSqr(a_-ctr) <= facSqr*radiusSqr
)
{
pHit.setMiss(false);
pHit.setPoint(ctr);
minRadiusSqr = radiusSqr;
}
}
// 3. Try midpoints of edges
// mid of edge A-B
{
point ctr = 0.5*(a_ + b_);
scalar radiusSqr = magSqr(a_ - ctr);
scalar testRadSrq = facSqr*radiusSqr;
if
(
radiusSqr < minRadiusSqr
&& magSqr(c_-ctr) <= testRadSrq
&& magSqr(d_-ctr) <= testRadSrq)
{
pHit.setMiss(false);
pHit.setPoint(ctr);
minRadiusSqr = radiusSqr;
}
}
// mid of edge A-C
{
point ctr = 0.5*(a_ + c_);
scalar radiusSqr = magSqr(a_ - ctr);
scalar testRadSrq = facSqr*radiusSqr;
if
(
radiusSqr < minRadiusSqr
&& magSqr(b_-ctr) <= testRadSrq
&& magSqr(d_-ctr) <= testRadSrq
)
{
pHit.setMiss(false);
pHit.setPoint(ctr);
minRadiusSqr = radiusSqr;
}
}
// mid of edge A-D
{
point ctr = 0.5*(a_ + d_);
scalar radiusSqr = magSqr(a_ - ctr);
scalar testRadSrq = facSqr*radiusSqr;
if
(
radiusSqr < minRadiusSqr
&& magSqr(b_-ctr) <= testRadSrq
&& magSqr(c_-ctr) <= testRadSrq
)
{
pHit.setMiss(false);
pHit.setPoint(ctr);
minRadiusSqr = radiusSqr;
}
}
// mid of edge B-C
{
point ctr = 0.5*(b_ + c_);
scalar radiusSqr = magSqr(b_ - ctr);
scalar testRadSrq = facSqr*radiusSqr;
if
(
radiusSqr < minRadiusSqr
&& magSqr(a_-ctr) <= testRadSrq
&& magSqr(d_-ctr) <= testRadSrq
)
{
pHit.setMiss(false);
pHit.setPoint(ctr);
minRadiusSqr = radiusSqr;
}
}
// mid of edge B-D
{
point ctr = 0.5*(b_ + d_);
scalar radiusSqr = magSqr(b_ - ctr);
scalar testRadSrq = facSqr*radiusSqr;
if
(
radiusSqr < minRadiusSqr
&& magSqr(a_-ctr) <= testRadSrq
&& magSqr(c_-ctr) <= testRadSrq)
{
pHit.setMiss(false);
pHit.setPoint(ctr);
minRadiusSqr = radiusSqr;
}
}
// mid of edge C-D
{
point ctr = 0.5*(c_ + d_);
scalar radiusSqr = magSqr(c_ - ctr);
scalar testRadSrq = facSqr*radiusSqr;
if
(
radiusSqr < minRadiusSqr
&& magSqr(a_-ctr) <= testRadSrq
&& magSqr(b_-ctr) <= testRadSrq
)
{
pHit.setMiss(false);
pHit.setPoint(ctr);
minRadiusSqr = radiusSqr;
}
}
pHit.setDistance(sqrt(minRadiusSqr));
return pHit;
}
Foam::pointHit Foam::face::ray
(
const point& p,
const vector& n,
const pointField& meshPoints,
const intersection::algorithm alg,
const intersection::direction dir
) const
{
point ctr = Foam::average(points(meshPoints));
scalar nearestHitDist = GREAT;
scalar nearestMissDist = GREAT;
bool eligible = false;
// Initialize to miss, distance = GREAT
pointHit nearest(p);
const labelList& f = *this;
label nPoints = size();
point nextPoint = ctr;
for (label pI = 0; pI < nPoints; pI++)
{
nextPoint = meshPoints[f[fcIndex(pI)]];
// Note: for best accuracy, centre point always comes last
// HJ, 9/Sep/2001
pointHit curHit = triPointRef
(
meshPoints[f[pI]],
nextPoint,
ctr
).ray(p, n, alg, dir);
if (curHit.hit())
{
if (Foam::mag(curHit.distance()) < Foam::mag(nearestHitDist))
{
nearestHitDist = curHit.distance();
nearest.setHit();
nearest.setPoint(curHit.hitPoint());
}
}
else if (!nearest.hit())
{
// Miss and no hit yet. Update miss statistics.
if (curHit.eligibleMiss())
{
eligible = true;
// Miss distance is the distance between the plane intersection
// point and the nearest point of the triangle
scalar missDist =
Foam::mag
(
p + curHit.distance()*n
- curHit.missPoint()
);
if (missDist < nearestMissDist)
{
nearestMissDist = missDist;
nearest.setDistance(curHit.distance());
nearest.setPoint(curHit.missPoint());
}
}
}
}
if (nearest.hit())
{
nearest.setDistance(nearestHitDist);
}
else
{
// Haven't hit a single face triangle
nearest.setMiss(eligible);
}
return nearest;
}
