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Remove self-intersecting faces #5650

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This commit is contained in:
Thomas Krijnen
2024-10-29 15:43:02 +01:00
parent fa07f184c3
commit 3d4988349a
1 changed files with 57 additions and 32 deletions
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src/ifcgeom/kernels/cgal/CgalConversionResult.cpp
+57 -32
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@@ -24,6 +24,28 @@ typedef Polyhedron::Facet_const_handle Facet_const_handle;
typedef Polyhedron::Halfedge_around_facet_const_circulator Halfedge_around_facet_circulator;
namespace {
template <typename Facet>
CGAL::Direction_3<Kernel_> newell(Facet& face) {
typename Kernel_::FT a(0), b(0), c(0);
CGAL::Polyhedron_3<Kernel_>::Halfedge_around_facet_const_circulator current_halfedge = face.facet_begin();
do {
auto& curr = current_halfedge->vertex()->point();
auto& next = current_halfedge->next()->vertex()->point();
a += (curr.y() - next.y()) * (curr.z() + next.z());
b += (curr.z() - next.z()) * (curr.x() + next.x());
c += (curr.x() - next.x()) * (curr.y() + next.y());
} while (++current_halfedge != face.facet_begin());
return CGAL::Direction_3<Kernel_>(a, b, c);
}
struct Plane_equation {
template <typename Facet>
typename Facet::Plane_3 operator()(Facet& face) {
typename Facet::Halfedge_handle h = face.halfedge();
return typename Facet::Plane_3(h->vertex()->point(), newell(face));
}
};
bool are_facets_coplanar(const Facet_const_handle& f1, const Facet_const_handle& f2) {
// Function to determine if two facets are coplanar
// You can use the normal vectors and the equation of the planes to determine coplanarity
@@ -80,15 +102,32 @@ ifcopenshell::geometry::CgalShape::CgalShape(const cgal_shape_t& shape, bool con
shape_ = shape;
convex_tag_ = convex;
std::set<cgal_shape_t::Facet_handle> faces_to_remove;
for (const auto& face : CGAL::faces(*shape_)) {
// @todo O^2 alert! Use aabb tree or box intersections
bool has_self_intersection = false;
auto V = newell(*face).to_vector();
if (V.squared_length() == 0) {
Logger::Warning("Removed face due to self-intersections");
faces_to_remove.insert(face);
continue;
}
auto C = face->halfedge()->vertex()->point();
auto transform_point = [&V, &C](const auto& p) {
auto dv = p - C;
return C + (dv - (dv * V) * V);
};
for (auto& he1 : CGAL::halfedges_around_face(face->halfedge(), *shape_)) {
CGAL::Segment_3<Kernel_> s1;
{
const auto& source = he1->vertex()->point();
const auto& target = he1->next()->vertex()->point();
s1 = { source, target };
s1 = {
transform_point(source),
transform_point(target)
};
}
for (auto& he2 : CGAL::halfedges_around_face(face->halfedge(), *shape_)) {
if (he1 == he2 || he1->next() == he2 || he2->next() == he1) {
@@ -99,17 +138,27 @@ ifcopenshell::geometry::CgalShape::CgalShape(const cgal_shape_t& shape, bool con
{
const auto& source = he2->vertex()->point();
const auto& target = he2->next()->vertex()->point();
s2 = { source, target };
s2 = {
transform_point(source),
transform_point(target)
};
}
if (CGAL::do_intersect(s1, s2)) {
has_self_intersection = true;
break;
if (CGAL::to_double((s1.start() - s2.end()).squared_length()) < 1.e-12 ||
CGAL::to_double((s1.end() - s2.end()).squared_length()) < 1.e-12 ||
CGAL::to_double((s1.start() - s2.start()).squared_length()) < 1.e-12 ||
CGAL::to_double((s1.end() - s2.start()).squared_length()) < 1.e-12 ||
CGAL::do_intersect(s1, s2))
{
Logger::Warning("Removed face due to self-intersections");
faces_to_remove.insert(face);
}
}
}
}
if (has_self_intersection) {
throw std::runtime_error("Self-intersection in facet boundary, not attempting triangulation");
{
for (auto& face : faces_to_remove) {
CGAL::Euler::remove_face(face->halfedge(), *shape_);
}
}
@@ -444,30 +493,6 @@ OpaqueCoordinate<3> ifcopenshell::geometry::CgalShape::position()
}
}
namespace {
template <typename Facet>
CGAL::Direction_3<Kernel_> newell(Facet& face) {
typename Kernel_::FT a(0), b(0), c(0);
CGAL::Polyhedron_3<Kernel_>::Halfedge_around_facet_const_circulator current_halfedge = face.facet_begin();
do {
auto& curr = current_halfedge->vertex()->point();
auto& next = current_halfedge->next()->vertex()->point();
a += (curr.y() - next.y()) * (curr.z() + next.z());
b += (curr.z() - next.z()) * (curr.x() + next.x());
c += (curr.x() - next.x()) * (curr.y() + next.y());
} while (++current_halfedge != face.facet_begin());
return CGAL::Direction_3<Kernel_>(a, b, c);
}
struct Plane_equation {
template <typename Facet>
typename Facet::Plane_3 operator()(Facet& face) {
typename Facet::Halfedge_handle h = face.halfedge();
return typename Facet::Plane_3(h->vertex()->point(), newell(face));
}
};
}
OpaqueCoordinate<3> ifcopenshell::geometry::CgalShape::axis()
{
to_poly();